The Adventures of Radon Ranger
Andreas C. George
©2013
Introduction
This book is written as an introduction to radon for the crop of radon rangers as well as those with
a general interest in the subject. For close to 35 years, I worked as a government scientist
specializing in radon and radiation safety. A collection of my research dating from 1963 to 1996 is
archived with the US Atomic Energy Commission (AEC) and the US Department of Energy
(DOE). In addition, I have published more than 96 scientific papers with the majority on radon
measurements, inhalation and radiation exposure in uranium mines and in residential buildings.
Most of my published work was presented in several International Symposia and Workshops.
During my long career from 1963 to today (50 years), I had the privilege of meeting and working
with hundreds of colleagues and researchers worldwide. Due to the large number of interactions,
the omission of any names in this short book is unintentional. I consider everyone I crossed paths
with to be integral part to this story. To do justice to this brief booklet, I had to begin to tell my
lifelong story from the day of my birth till 2013. It was a long and interesting ride. I hope I am
presenting the reader with a valuable and readable overview of a long and memorable experience.
I tried to bring the reader up to speed about the evolution of radon and about the most important
activities concerning radon. In addition to the chronological presentation of events several parts of
the book are devoted to special topics that I had intimate knowledge of. I hope that I provided an
introduction to radon for the new radon rangers and a fresh update for those who are already
full-blown radon professionals. This book is written for people who have some radiation
background and for people that will get some benefit from the history and development of the
radon subject.
It all began in the small town of Clairton Pennsylvania. In 1920, my father left his homeland
the island of Cyprus to find work in America. From 1878 through 1960, Cyprus was a British
colony. At the end of World War I, many young men were without work and had to look for
opportunities in other lands. Some went to Britain, Egypt and South Africa where it was easier to
immigrate. Many others took advantage of the opening of the immigration quota that was
favorable for Cypriot men to enter the United States. My father was one of the hundreds of young
Cypriots who left their little island for the shores of America. Just before leaving for America, my
future parents became engaged, a union that was to last eight years until my father returned to
Cyprus in 1928 to marry my mother. Where can you find this kind of loyalty and commitment
today?
In 1928, my father returned to Cyprus and kept his promise to marry my mother. In the summer of
1928, my father Christodoulos and my mother Katerina as husband and wife sailed from Greece
for the shores of New York. At that time there were no commercial airline flights and the long trip
of 5,500 miles was by a small boat from Cyprus to Greece and by ocean liner from Greece to the
port of New York. They entered the US and cleared immigration officially in July 1928. The small
town of Clairton, Pennsylvania was their final destination. Clairton located fifteen miles south of
Pittsburgh, had one of the largest steel mills. It was operated by Carnegie Steel Works next to the
banks of the Monogahela River. Every day my father walked three blocks from his apartment on
Spruce Street to go to work.
My oldest brother George was born in 1929 followed by my second brother Constantine (Gus) in
1930. I was the third son born on April 23, 1931 seventeen months after the Wall Street crash that
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marked the beginning of a decade of high unemployment.
Mining and the steel industries suffered greatly after the crash. My father’s six-day work-week
was reduced to just two days. The US economy reached bottom in 1932-33 and Herbert Hoover
lost the 1932 presidential election to Franklin Delano Roosevelt in a landslide victory.
The Great Depression left my parents with no other option but to pack up and return to Cyprus
their native island the birthplace of Aphrodite the Goddess of Love.
In August 1932, when I was fifteen months old my family left Pennsylvania and returned to
Cyprus. The return trip was long via an Italian steamship making stops in Naples Italy and Piraeus
Greece. From Greece the family reached its final destination on a smaller ship. The savings that
my father accumulated in twelve years were just enough to purchase more land in Cyprus and
revert back to farming and vegetable growing as a source of income. While my two older brothers
were baptized in the US by relatives who stayed in the US to wait for the economy to recover, my
parents held back on my christening to take place in Cyprus by one of my father’s best friends.
Also, my mother wanted my christening to take place at the Monastery of Saint Andrew at the very
east end of the island and about 150 miles from Israel. Incidentally, although my diminutive name
Andy is derived from Saint Andrew or Saint Andreas (the brother of Saint Peter), I am by no
means a saint.
From 1932 through 1950, my brothers and I grew up in our parent’s new home that was funded in
part by my maternal grandparents as part of our mother’s dowry as well as by the money our father
sent from America. Our home was in a small village of farmers and shepherds, seven miles east of
Nicosia the capital of Cyprus. I attended public school at the village and junior and high school in
Nicosia. When staying in Nicosia, I lived with relatives and went back to the village on weekends.
School hours were from 7:00 AM till 2:00 PM six days a week. On Saturday after school I returned
to the village. From 1944-45 during World War II, there was no means of transportation to the
village so on many Saturdays I walked the seven miles back to the village. Sometimes, I was given
a ride on someone’s bicycle or rode back on a she jackass with my younger brother Nicholas who
brought her to Nicosia to take me home to Neon Chorion our village. Other times, I hitched a ride
on a British army truck that dropped me off about one mile from home.
During the summer recess, my favorite pastimes were working on the farm, sleeping outdoors
under a lemon tree and getting up before sunrise to feast on figs from trees that I planted myself.
In Cyprus, we did not have a Christmas tree celebration. The village schoolteacher instructed us to
plant trees and live off their fruit rather than cutting them down. My brothers and I planted many
trees on our land, especially olive, lemon and fig trees. In addition, we grew our own vegetables
and sold tomatoes, beans, eggplants, potatoes cotton and sesame all grown on our farm. We raised
chickens, rabbits and goats. From the goats we made fresh yogurt and the famous halloumi cheese.
The only things we bought at the store were sugar and rice.
When I was about ten years old, I had become adept in hooking up two oxen to a wooden cart to
transport farm goods. I felt like a big shot driving my cart through the village by myself. My oxen
driven cart was the equivalent to a modern tractor. From the age of twelve on, I was able to plough
the soil with the same pair of oxen and separate the grain from the straw. Usually, all these tasks
were carried out from 6 AM till 11:00 AM. The summers were very hot and all work outdoors
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ceased from 11:00 AM to 3:00PM. Unfinished work sometimes had to be conducted after 3:00 PM
until the early evening hours.
From 1944-1950, I attended the Pancyprian Gymnasium the most prestigious high school on the
island. All subjects were conducted in Modern Greek with a daily dose of Ancient Greek. In my
senior year during the Christmas recess, I was assigned to memorize two pages of Homer’s Iliad in
the original language. Others had to memorize the next two pages and so on. By the time we
returned to School about sixty pages were recited in the classroom for the teacher’s evaluation.
Besides modern and ancient Greek we had to take two years of Latin, three years of French and
four years of English. My overall experience at the school was a good grasp of the Classics,
geometry, trigonometry, algebra, physics, little chemistry, religious classes and daily gymnastics.
As an American born citizen, my dream was to return to America and continue my education and
realize the American dream. My two older brothers had already left Cyprus in 1946 and 1947
respectively. On August 4, 1950, I left Cyprus for Greece and from there headed to New York. Just
before sunrise on August 29, 1950 our ship passed the Statue of Liberty and docked in Hoboken on
the New Jersey side of the Hudson River. The sun was about to rise when we passed by Ellis Island
and had my first look at the Statue of Liberty a gift from France and a marvel of French
architecture. Being an American citizen by birth, I was allowed ashore very quickly.
My brother George and an uncle picked me up in a taxi that drove us to Manhattan under the
Hudson River through the Lincoln Tunnel. The Lincoln Tunnel was the first American
engineering innovation that amazed me a few minutes after I stepped off the ocean liner.
Two weeks after my arrival to New York I found work in a fur shop. From September through
Christmas I was cutting earmuffs from large pieces of fur using a dye.
During the week of December 23 through January 5, 1950, I went by Bus to spend the holidays
with close relatives in Clairton the place of my birth. It was my first visit back my family left in
1932. In Clairton I stayed with my Uncle John’s family and rediscovered the city of my birth. At
the same time, I visited close relatives who lived in Donora, PA a few miles west of Clairton.
In Donora, I learned about one of the worst air pollution incidents in the US history that occurred
in October 1948. The city had a problem with smog buildup. Researchers concluded that the
pollution from the zinc plant that generated hydrogen fluoride and sulfur dioxide during the zinc
smelting process had become trapped by the stagnant air during a temperature inversion condition
that hang over Donora for four days. During the temperature inversion, warmer air aloft trapped
the pollution in a layer of colder air near the surface. On October 31, the rain broke the inversion
condition and saved the town from a worse incident. Some of my family members became ill but
recovered fully. Unfortunately, 20 Donora citizens died and about one third of the town’s
population of 14,000 had been sickened. At that time, I was not aware of such incidents until I
earned my MS in Air Pollution at the City College of New York in 1972. In one of my reports in
the Civil Engineering department at the college I studied many of these incidents including the one
in Donora. The Donora smog marked one of the incidents where Americans recognized that
exposure to large amounts of pollution in a short period of time can result in injuries and fatalities.
The Donora event is often credited for helping to trigger the clean air movement in the US, whose
crowning achievement was the Clean Air Act of 1970. Today, about 6,000 people still live in
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Donora as a result of closing the US Steel’s Donora Zinc Works and its American Steel and Wire
plant.
For the next sixteen months I lived in Manhattan and worked in restaurants during the day and
attending night classes at New York University to brush up my English vocabulary. I lived in
Manhattan in a small furnished room and shared a bathroom and wash sink in the hallway with five
other residents. It was hard for me in the first few months working six days a week in addition to
two evening classes. On Sundays, my day off, I went to Times Square to unwind and enjoy the
lively atmosphere of the place. I visited most of museums and other places of interest. I have
become an expert on New York and on its cultural activities. Back then for a subway fare of ten
cents you could travel all day and experience the five boroughs of New York City.
During the Korean War, the draft was mandatory. My older brother George was drafted in the
Army and sent to Germany to serve in the medical corps for two years. My brother Constantine
volunteered in 1948 to serve with the 82nd Airborne Division as a paratrooper. In 1951, he was
shipped to Korea and became severely wounded at the battlefield. With two brothers in the Armed
Forces I thought, I may be classified as exempt from service in the military. Well I was mistaken.
In early January 1952, I was asked to appear at the local Selective Service Branch for an interview
and possible selection to serve Uncle Sam. Two weeks later, I received a letter informing me to go
downtown by subway for my medical examination and fitness for army duty. Enclosed were two
dimes for the trip. The doctors found me physically and mentally fit for military service. Soon
afterwards, I received a second letter with one dime enclosed congratulating me for the honor to
serve my country.
On Valentine’s Day in 1952 I reported for induction into the Army. Buses picked all the cadets for
the hour-long ride to Camp Kilmer, New Jersey. Forty years later, when I went to teach a class and
present a seminar on the particle size distribution of radon decay products to students from Rutgers
University to my surprise I found myself in the midst of the Army Barracks where I spent my first
two weeks for orientation. All newly drafted civilians were required to attend orientation and
receive the necessary vaccinations. We also underwent tests for skill and proficiency to determine
in which branch of the Armed Forces we were most suitable to serve.
I was selected to train in antiaircraft artillery and was shipped by plane to Fort Bliss, outside of El
Paso, Texas. There were no missiles yet but we were told some new weaponry was coming to Fort
Bliss in the near future for testing at the firing range.
El Paso was as a very small town in 1952. After eight weeks of basic training and instruction on
antiaircraft guns I was given leave to visit the town and even to cross the Rio Grande River Bridge
into Juarez Mexico where I saw my first live bullfight. Patricia McCormick, the first American
woman bullfighter was featured on that day along with other male bullfighters. The Mexican beer
tasted real good but after the consumption of one bottle things began to spin around me. My limit
was two bottles before I returned back to Fort Bliss and the camp.
Weeks later, I was headed back to New York by bus for my embarkation to Europe and final
destination Trieste, Italy. In 1952, there was a dispute between Italy and Yugoslavia as to who had
the legitimate sovereignty over the villages in the vicinity of the city of Trieste. An American and
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a British Brigade were stationed in Trieste to keep the Italians and the Yugoslavians from going to
war over the disputed territory. I was assigned to the First platoon of the 88th Reconnaissance
Company because I was fluent in Greek a language that was spoken by some minorities in the
Balkan countries. Our unit was stationed in Duino a picturesque suburb of Trieste near a castle that
served as the headquarters of the British brigade. The remainder of the American brigade was
stationed in the city of Trieste 10 miles away. During my first six months in Trieste, things were
quiet without any incidents between the two parties. On our shirts and jackets the Army had sewn
the insignia TRUST identifying us as “Trieste United States Troops”. I still have my jacket that is
too small to fit on my older body. One of the advantages that we enjoyed while serving in Trieste
we did not have to serve in the kitchen (pull Kitchen Police duty- KP as they say in the Army). For
two dollars per month deducted from our monthly pay, local women cooked and served our meals
under the supervision of the mess hall sergeant. The local women served us and cleaned after each
meal. When we went on a 2-5 day field exercise we took along a male local civilian to perform all
kitchen duties. Although I was not a smoker, I purchased my allotment of cigarettes from the Post
Exchange for nine cents a pack or 90 cents a carton. Civilian local women did my laundry and
tailoring in exchange with cigarettes. I sold the balance of my cigarette allotment to the local
policeman for 25 cents/pack, which he probably sold to the locals at black market prices. American
unfiltered cigarettes were very popular and in great demand in Europe seven years after the end of
World War II.
Looking back, the celebration of American holidays in the army impressed most and made my stay
more pleasant. In particular, in 1952, my first Thanksgiving in the army stands out more than any
other holiday. I still have the colorful menu listing shrimp cocktail, salads, roast turkey and
Virginia baked ham with all the holiday trimmings.
The army service afforded me adequate time to study and improve my English vocabulary by
reading books that would prepare me to gain access to a college after my discharge. I always had
an inclination in biological sciences and how the human body functions as a whole. I initiated my
self-studies by reading the book “The Machinery of the Body” which I found very helpful and easy
to understand. Like all sciences many of the words in Biology have Greek derivations making my
comprehension rather pleasant. Another source of reading that I found very useful and informative
was the weekly newspaper “The Blue Devil” published by the American brigade stationed in
Trieste. It was a very professional newspaper that brought the news from home and the brigade.
The two years in the Army provided me with a good grasp of the English language and exposed me
to different cultures. It took many years to lose my Cypriot accent to the point that is barely
detectable today.
After nine months in the Army, the commanding General of the Brigade decided that it was time to
establish an Artillery Battery. Since my basic training in Fort Bliss Texas was in antiaircraft and
artillery weapons I was selected to join the new 12th Artillery Battery. I was promoted to corporal
and from that time I was known as “Corporal George”. After several months as an artillery trainee
the time had come to fire the 155 mm artillery guns. There was no firing range in Trieste making it
necessary to drive for two days from Trieste to Munich Germany to practice firing similar guns.
The entire Artillery Battery was loaded in several Army trucks and we were driven through the
Italian and Swiss Alps to Munich. The long journey took 2 days with one night camping under the
feet of the Swiss Alps. On the evening that we arrived in Munich, I was selected to serve as a
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military policeman. My job would be going around in local nightclubs with another GI who was
stationed in Munich for several years to keep an eye on American soldiers and make sure they
stayed out of trouble. The next morning, my artillery company left early for the firing range
without me so I could get some sleep. I planned to go to the firing range the following day but it
wasn’t meant to be. The next day word came that the Italians and Yugoslavians were raising
tensions again over the disputed territory of Trieste, forcing us to fly back there immediately. The
truck drivers were left behind to drive the empty trucks back to the home base in Trieste. Now you
know that corporal George a squad leader in the 12th Artillery Battery never had the chance to fire
those big guns for which he was trained.
When we returned to Trieste, the two opposing countries came to some kind of understanding and
decided to begin negotiating their differences instead of going to war. Three months later, I
completed my service obligation to Uncle Sam and returned to New York to pursue my college
education. Overall, my Army service in Europe was quite uneventful. Some young soldiers who
went through the same basic training in Fort Bliss Texas were shipped to Korea, one of which was
killed in action. Another positive aspect of my military service overseas was to take two separate
vacations one to Rome and another to Paris. On a third 3-day shorter vacation in July 1953, I joined
a group that visited the Dalmatian Coast of Yugoslavia. It was an interesting trip going to another
country with a different brand of Communism expounded by Tito but still hostile to the United
States.
While I was overseas, my older brother George returned to the US from Germany and back to
Clairton to marry the girl who was born in the same apartment building as my brothers and I. My
brother Constantine (Gus) returned from Korea after he spent three months in a Hawaii Army
hospital to recover from severe wounds he suffered on the Korean battlefield.
In February 1954, I applied to New York City Community College and I was accepted in the
Medical Technology Department. I earned an Associate Science degree that prepared me to get a
job in a hospital and later at the New York City Department of Health. I acquired extensive
experience in hematology, bacteriology, histology, and blood analysis. Thanks to the army, I
received my associate degree without having to pay any tuition. I also collected a nominal
compensation from the GI bill benefit.
During the first semester in college I met my future wife who was in her senior year in high school.
In the afternoons after school she worked at her father’s coffee shop on 8th Avenue and on the
corner of 43rd street in Manhattan one short block from the famous 42nd street and Times Square.
On many afternoons after classes I went to an employment agency near her father’s coffee shop to
look for night or weekend work. Afterwards, I do stop at the coffee shop and she’d squeeze fresh
orange juice for me for 15 cents. To impress her I always left her a tip of 25 cents.
After several months of talking in her father’s coffee shop we started going out together taking
long walks on 8th Avenue to Central Park West. We spent many early evenings in the park mostly
in the same place John Lennon made famous twenty years later as “Strawberry Fields”. Just before
my wife’s graduation I helped her with her chemistry finals and when she graduated I escorted her
to her prom. For a person who came from a European and small village background I was fortunate
to experience many of the American traditions and customs. I have many fond memories of 42nd
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street. I took my future wife to the movies on 42nd street where we saw two full-length movies, a
cartoon and the newsreels late at night for just twenty-five cents. Before the mid –60’s it was one
of the safest and well-kept places of Manhattan. After the mid 1960’s the area was falling apart
with the introduction of drugs and an increase in crime.
After I completed three semesters in college, I got married in the Holy Trinity Church on East 74th
street. The wedding reception was held in the newly renovated Empire Hotel a block from the
present site of Lincoln Center. As a married couple we moved into a 2-bedroom apartment in the
Bronx. Six months later I graduated from college and began to work in a New York City Hospital.
My wife found work at a bank near the site where the World Trade Center was built a few years
later. Salaries for someone with my training at that time ranged from $4,500 -$5,500 a year enough
to survive on if you were single. In the meantime we started a family. My first daughter Stella was
born in 1956 and Diana in 1957. My plan was to go back to college and earn a BS degree in
Biology with a minor in chemistry. I kept working full time during the day and attended Brooklyn
College at night and Saturdays earning my BS degree in less than three years.
My monthly allotment from the GI Bill benefit increased to $ 500.00 per month to keep up with my
expanding family. To supplement my income I worked at night on the weekends in a restaurant
near Radio City Hall. At that time, I drove my car and parked it near the restaurant making it
possible for me to leave Manhattan at 1:00 AM and get to my residence in the Bronx in 30 minutes.
Today, there is no free parking anywhere in the streets. You must park in designated parking lots
that charge more than $40 for an 8-hr stay.
My wife stayed home as a full time mom and in June 1960 gave birth to our son Christopher. With
BS degree under my belt I took a Civil Service examination as a Medical Technologist with the
Veterans Administration. I scored high and with the additional five points from being a veteran I
jumped to the top of the list. Disabled veterans were given ten points. One month after the list was
publicized, I was offered a job in a VA Hospital in New England. For several reasons I declined the
offer and accepted a local position with the New York City Department of Health Office of
Radiation Control. From that moment, I abandoned test tubes and microscopes to pursue a career
in radiation protection in medical facilities. At the same time, I started my graduate studies at
Hunter College. In the graduate program they offered a course in radiation biology that I found
very important as an extension to my major in undergraduate school.
Hunter College in cooperation with Sloan Kettering Center offered other courses on radiation
fundamentals and radiation protection taught by Dr. John Laughlin one the founders of the Health
Physics Society.
New York City was one of the first cities to set up an Office of Radiation Control to inspect all
facilities that used X-ray equipment or administered nuclear medicine for therapeutic purposes.
During the first two months after I joined the Office of Radiation Control I accompanied Earl, an
experienced radiation inspector, to go out in the field to conduct radiation inspections and prepare
reports. Earl was older than I and we became close friends. He offered unsolicited advice and
guidance. He kept telling me that with my educational background I should look for a more
challenging position in the radiation field. Most of the radiation inspectors where I worked were
practicing podiatrists. I believe they had some previous experience with X-ray machines that made
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them good radiation inspectors. My teammate and I inspected the biggest hospitals in Manhattan
and the Bronx.
In the next two and one half years I operated on my own inspecting dental X-ray machines,
doctors’ offices and hospitals where X-ray, fluoroscope machines and radioactive sources were
used in nuclear medicine. Radiation protection was in its infancy. As a radiation inspector, I found
that most doctors and dentists that used radiation machines had very little knowledge about
radiation protection and in the proper use of their equipment. When I inspected a dentist’s office I
found that he was using his dental X-ray machine to take an X-ray of a patient with an arm fracture
sent by his wife, a medical doctor. On another visit for inspection of a fluoroscope machine the
doctor did not know where his lead apron was. After I searched I found it folded on top of his
upright machine full of dust indicating that the doctor did not use it while conducting a
fluoroscopic procedure. In fluoroscopic examinations the X-ray machine is on for longer time
periods than a standard chest X-ray. A physician wearing no lead apron was getting irradiated
unnecessarily. Even some radiologists in 1961, were not sufficiently trained in radiation
protection. Here is a case where a radiologist using a radium capsule to treat cervical cancer had it
stored unshielded in a metal cabinet in the room where doctors changed their clothing. Those
radium capsules probably had curie quantities of radium, radon and radon decay products.
We have come a long way now by establishing radiation protection programs on city, state and
federal levels. Today, thousands of Radiation Safety Officers in the U.S provide first class
radiation protection second to none.
In the meantime, Earl continued the search for employment opportunities for me. He thought he
was too old to make a change. He and his wife were childless and being close to retirement he
decided to stay put. In June 1963 when he saw an ad about an intern position in the New York
Operations Office of the U.S. Atomic Energy Commission he recommended that I follow up on it.
The position was for a college graduate with a degree in one of the sciences to start at Grade-9 that
meant a jump in salary from $5,500 to $10,000 per year. By this time I completed my graduate MS
degree in Biological and Biophysical Science at Hunter College placing me in a good position to
be hired. My interview with the AEC was conducted in August 1963 and went well. A week later I
was informed that I was selected in the intern program and that I could begin working as soon as
my FBI clearance was finalized. The position required Q clearance that took two months to
conduct and complete. The first day at my new job was on October 15, 1963. I was placed in the
Health Protection Engineering Division of the Health and Safety Laboratory (HASL) a lab from
the old Manhattan Project.
In the first three months I was assigned to a health physics specialist that conducted inspections at
research reactors that were contractors of the AEC. In January 1964 I was asked to develop a
sampling system to determine the concentration of I-131 released during an accident involving
reactors and nuclear fuel reprocessing plants. Iodine -131 is of particular importance as a
radioactive contaminant because of its low MPC in air (3 x 10-9 uCi/cc). My assignment was to
develop a quick method to detect the released Iodine so measures can be taken to avoid exposure to
personnel and the public in the vicinity of a reactor. Activated carbon was investigated for its
collection efficiency for I-131 by adsorption. Twenty years later, I used the same principle to
collect radon on activated carbon and a new radon testing industry was born.
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I cut several sections of plastic tubing of 0.53 inches in diameter by 2 inches in length. The
Column of activated carbon (Barnaby-Cheney Chemical Co. size MH2) inside the cartridge was
about 1.5 inches supported by snap wire rings. The fabricated cartridges were calibrated by using
the portable 3" x 3" thallium activated sodium iodide crystal with a well in which the cartridge was
counted. In February 1964, I loaded the sampling equipment on a government van to proceed to
Brookhaven National Laboratory located about 70 miles east of Manhattan. The Long Island
expressway did not extend far enough to reach Brookhaven Lab. There was some light snow on
that day and I reached my destination after 2 hours of hazardous driving conditions. Sampling was
usually for 15 - 30 minutes at 1 ft3/min. I could not do immediate counting since the portable
analyzer was back at HASL. Our data for I-131 agreed very well with the Brookhaven
measurement results. The cartridge fabricated at HASL was found to be satisfactory for a quick
estimation of I-131 at the Brookhaven reactor and off-site areas such as the Squibb Labs. To
confirm the accuracy of the I-131 concentration the same cartridge can be counted 2-3 days later
after collection allowing the other short-lived isotopes to decay.
After six months in the intern program I was offered a position with AEC at the Nevada Test Site.
I went there for an interview and observed some of the ongoing activities. The drive from Las
Vegas to the test site is about 80 miles. I was driven through sunshine, rain and some snow before
we reached the place. Nuclear testing was conducted underground as evidenced by the presence of
collapsed areas on the surface. When I returned to New York and told my wife about the prospect
of moving closer to the test site. She was against the offer for the Nevada position.
As luck will have it, a position as Industrial Hygienist was opened at HASL in the Health
Protection Engineering Division where I spent my last six months as an intern. I accepted the
position at 376 Hudson Street in the West Village area of Manhattan where I was to spend another
33 years until I retired from the federal government. It was the perfect opportunity for me to work
with some of the most dedicated government employees and at the same time I avoided uprooting
my family from close family, schoolmates and friends.
The Health and Safety Laboratory (HASL), was part of the New York Operations Office of the US
Atomic Energy Commission (AEC). It was set up in 1947 as central laboratory facility in the
Medical Division of the AEC. The name HASL was actually adapted in 1953. The interest and
competence of the staff broadened rapidly in the field of engineering and physical sciences. They
were called to aid and control airborne dusts, direct radiation hazards, and fire and safety in AEC
contractor plants. After I arrived at HASL the laboratory devoted many years to problems
estimating the radiation exposure of uranium miners. This included aerosol studies and the
development of instrumentation and methods of measurement. HASL was involved heavily in
setting up national and worldwide monitoring networks to measure radioactive fallout following
nuclear and thermonuclear testing and in measuring natural background, both cosmic and
terrestrial radiation. The laboratory developed techniques of radiochemical analysis and produced
the renowned Standard Procedures Manual and provided working standards for other laboratories
in the US and abroad to check procedures and perform inter-comparisons and inter-calibrations.
Several projects materialized as soon as I was hired to investigate the re-suspension of long-lived
radioactivity from surfaces in a contaminated building. I collected air samples to determine the
fraction of re-suspended radioactive particles while I was running a dolly cart back and forth along
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the contaminated floor. Another large project was to investigate the inhalation and retention of
uranium by mill workers in the Fernald plant near Cincinnati and in the Ashtabula plant near
Cleveland Ohio. In both plants, I followed the workers with a portable sampling pump and filter
holder to collect the airborne uranium near the breathing zones during the day shift. Urine and
fecal samples were collected from each worker and from each HASL employee. These samples
were sent to New York for radiochemical analysis to determine the rate of uranium elimination. I
believe a journal article was published in the Journal of Industrial Hygiene presenting the results of
the study.
Another concern that involved the AEC and its contractors was the impact of radioactive
gases from the operation of Linear Accelerators (LINACS). As higher energy accelerators have
become operational new problems in radiation measurements have emerged. The accelerators
were financed by the AEC and the agency had the responsibility to protect the operators of the
high-energy machines from radioactive gases and ozone.
We were directed to investigate the presence of these gases at the Yale University LINAC in New
Haven Connecticut and at the Rensselaer Polytechnic Institute (RPI) Troy New York. I was
assigned to conduct this project and develop the appropriate instrumentation to measure and
evaluate the hazards from radio-activated air and ozone during the operation of the two LINACS.
For measuring ozone a radio-chemist from HASL came along to sample the concentration of
ozone. The buildup of Nitrogen-13 and Oxygen-15 are the principal gases produced by the
(gamma-N reaction). Their concentration depended on the beam power and duration of operation,
type of target, and ventilation. The main objective was to study the residual gases that constitute
exposure to personnel who enter the accelerator room after the LINAC is shut down. I researched
the type of radioactivity involved in LINACS to guide me in the fabrication of the specific
counting equipment. The gamma-N reaction in the operation of LINACS produces N-13, O –15,
Ozone and induces short-lived radioactivity in the building materials.
Both the N-13 and O-15 are positron emitters with half-lives and energies of 10 min and 1.2 MeV
and 2 min and 1.68 MeV respectively. I started to construct two new special monitoring devices
because there was a lack of commercial instruments at the time.
One monitor consisted of a 5 -gallon polyethylene bottle in which the in-house instrumentation
department and machine shop mounted through the neck of the bottle an Amperex GM tube and
provided input and output ports for sampling the radioactive gases. The second monitor was
fabricated from a 7- inch diameter and 26- inch long lucite tube. A Tracerlab MD -11 GM tube
mounted axially provided a better sensitivity for the radioactive gases. Both monitors were
calibrated with Krypton-85 a beta emitter. Range-energy corrections to the energies of N-13 and
O-15 were extrapolated from the beta energy of Krypton-85 by taking the ratio of the GM tube
response to P-32 with a beta energy of 1.2 MeV for N-13 and 1.68 MeV for O-15. Naomi Harley
the foremost radio-chemist and electrical engineer at HASL made these corrections for me. The
lowest detectable concentration for both monitors was about 0.1 of the MPC of the radioactive
gases. Ozone produced by the unshielded electron beam is a toxic gas. Its decomposition is
exponential characterized by a half-life of about 35 minutes. The strong smell of ozone persisted
for some time after the LINAC was shut down. Laboratory tests showed tygon tubing to be
unsatisfactory for sampling ozone and I switched to teflon tubing. Rubber tubing was not even
10
considered because in laboratory tests it showed severe cracking in the presence of ozone.
The radioactive gases were identified by following their decay patterns after air samples from the
accelerator room were sealed in the monitors for periods of 30-60 minutes. The graphical analysis
of the plots made it possible to identify clearly the half-lives of N-13 and O-15. Dust collected on
filters showed only N-13 and the radon decay product Pb-214. There was no detection of O-15.
The results of the extensive measurements at both LINACS at normal experimental conditions
showed concentrations of the radioactive gases as high as 5x10-4 μCi/cc and 0.8 ppm of ozone. The
MPCs for N-13 and O-15 are 2.3 x 10-6 μCi/cc and 2.0 x 10-6 μCi/cc respectively. The threshold
limit for ozone is 0.1 ppm. Fortunately, the pungent smell of Ozone can be detected by the human
nose at concentrations below the threshold limit. The investigation of the conditions at the two
LINACS showed that by using a combination of shielding, ventilation and the regulation of entry
to target areas radiation exposure from N-13 and O-15 was held to insignificant levels. Because of
the uncertain effects of ozone in man exposure to ozone should be regulated as carefully as are
exposures to radiation. Excessive exposure to 5 ppm of Ozone may cause pulmonary edema,
hemorrhage and death.
The study at the two LINACS was my first big project. It was a big challenge for me that proved to
be very useful in furthering my education in radiation measurements and radiation protection. The
cooperation and assistance provided by the late Robert Ryan the RSO at RPI and George Holeman
the RSO at Yale was greatly appreciated.
In the summer of 1965, I was asked to make an oral presentation of my findings at the Annual
Health Physics Society meeting in Los Angeles. I was excited and apprehensive about the fact that
I was going to give my first oral presentation to such a prestigious group of experts. There was a
special session on Accelerators chaired by the late Dade Patterson (an authority on accelerators).
My paper scheduled for 20 minutes, was the last presentation on Thursday the last day of the
annual meeting. How do you reduce a 41- page paper to 20-minute presentation? It was not very
easy. I covered the essence of the study in the 20 minutes I was given. Mr Patterson kindly asked
me to stop without summarizing the results of the study. He was worried that members of the
audience that had to leave to catch their return flights to their hometowns. He told the audience to
read the long paper when it gets published or they could contact me directly some other time.
While I was investigating the condition of radiation and Ozone exposures at the two LINACS,
an important Symposium on inhaled radioactive particles and gases was taking place in Hanford
Richland Washington. Top scientists in their field of work presented the latest information on a
topic that was gaining importance throughout the world scientific community. A good portion of
the symposium was addressing the health risk from radon and radon decay products. The
proceedings of the Hanford Symposium were published in a special issue of the Health Physics
Society Journal as Volume 10, Number 12 in December 1964.
I believe that this was the first time that 20 distinguished scientists from 8 foreign nations and
another 130 from the U.S. descended on the Hanford Biology Laboratory to present their work on
the characterization of inhaled radioactive particles and gases. In the special session on lung
dosimetry some of the most re-known scientists in the field presented the latest lung models that
11
estimate the lung dose from the inhalation of radon and radon decay products. In the late 1960’s I
met most of these scientists and I was grateful that they took the initiative to undertake the study
that estimated the health effects from inhaling radon and radon decay products. Among these
pioneers were Drs. Saccomanno and Archer who I believe were the first to observe that most of the
lung cancers among uranium miners were of the undifferentiated variety of tumors and of the oat
cell variety. Dr. Saccomanno, a pathologist performed autopsies on uranium miners at St. Mary’s
and Veterans Hospital in Grand Junction Colorado. Drs. Altshuler, Nelson and Kuschner from
New York University and the Department of Environmental Medicine presented a very
comprehensive inhalation model that estimated the lung tissue dose from the inhalation of radon
and radon decay products. In a parallel study Dr. Jacobi from Germany presented an invaluable
lung model that estimated the dose to the human respiratory tract by the inhalation of short-lived
radon and radon decay products.
Many questions were raised after the Hanford Symposium especially what was the particle size
distribution of radon decay products and what was the fraction retained in the lungs of
underground miners. The state of the working conditions in the mines at that time was the
responsibility of the U.S. Atomic Energy Commission my employer. Unfortunately uranium
mining companies never extended an invitation for us to investigate radon and radon decay
product concentrations, particle size and respiratory deposition. It took another two years after the
hearings of the Joint Committee on Atomic Energy on the radiation exposure of uranium miners to
address the radon problems in underground mines. The U.S. AEC finally decided to address some
of the questions that were raised at the Hanford Symposium and by the findings of the US PHS
epidemiological study.
My earliest assignments at HASL dealing with radon issues was to set up a radon calibration
facility that was destined to serve as the standards facility for radon inter-comparisons and
inter-calibrations in the US and worldwide for 35 years..
Early in 1965, HASL was approached by Dr. Gordon Stewart and Dr. Douglas Simpson from the
AECL at Chalk River Canada offering their assistance and cooperation and a Canadian uranium
mine for us to test some of the instruments and methods that we were planning to use to investigate
the conditions in underground mines and assess the exposure of miners to radon and radon decay
products. In preparation for the trip to the Canadian uranium mine, the HASL dust room the size of
a small bedroom was converted into a radon and radon decay product test facility to evaluate and
calibrate measuring instruments and methods that we were planning to use in the study. The radon
calibration facility remained operational from 1964 through 2,000 when DOE ceased to support
the radon program and the US EPA being the federal regulatory agency took over the
responsibility to provide radon calibration facilities in support of the expanding radon program.
I set up and supervised the maintenance and operation of the facility from 1965 till 1996 when I
retired from the U.S. DOE. In preparation for the Canadian visit, some of my colleagues and I
spent several months in 1965 and 1966 developing and testing instruments and equipment to
measure total respiratory deposition as a function of tidal and minute volume and breathing rate.
We tested the new equipment in the laboratory using six HASL employees breathing indoor air
and outside air from an open window on the 5th floor. I had to get permission from the security
department of the AEC, NY Operations Office to unlock the window. All windows on the 4th 5th
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and 8th floors of the building occupied by the AEC and HASL personnel were kept locked at all
times for security reasons. The respiratory deposition apparatus was also tested in the
Schwartzwalder mine near Golden Colorado on one subject (me) with good results.
For particle size measurements in a Canadian mine, I constructed a Zeleny Tube that measures
particle mobility from 1.8 - 0.005 cm2/Volt-sec. For lower mobility, down to 0.00005
cm2/Volt-sec, a parallel plate electrostatic precipitator was constructed by Jess Thomas (For some
reason Jess called it the “Baby Doll” In addition to measuring the electric mobility of radon decay
products we constructed a compact diffusion battery an early version of the more sophisticated
diffusion batteries that were developed 3-5 years later. This first diffusion battery gave us an
approximation of the effective diffusion diameter of radon decay products. The concentration of
the individual radon decay product measurements were determined by alpha counting and
recording the counting data on a strip-chart recorder in conjunction with the Tsivoglou Method.
In June 1966 and in July 1967 myself and two colleagues flew from HASL to the uranium mine
operated by Eldorado Mining and Refining Co. at Beaverlodge in the Canadian Province of
Saskatchewan. There were no roads to the mine area. Access was only by plane. The Mining Co
plane piloted by bush pilots was used for carrying provisions, passengers, miners and members of
their families and of course for transporting the refined ore in 55-gallon drums.
On our second return trip from the mine we sat in the rear part of the airplane behind twenty
55-gallon drums of refined uranium fastened somehow to prevent them from rolling down on the
passengers when the plane began to gain altitude. It was a scary ride worrying about those heavy
drums becoming loose and crushing us to death
The Eldorado uranium mine is 4,500 feet deep with drifts extending horizontally 500-1000 meters
under the Northern shore of Lake Athabasca. The lake located in the Northwest frontier is 176
miles long and 31 miles at its maximum width. It is the 8th largest lake in Canada. In 1961 the
world lake trout weighing 112 pounds was caught in it. One evening the mine manager invited us
for dinner to feast on the 22 pound trout caught in the lake. During the daytime near the lake we
had to keep the flies from biting us by using tree branches. I have never seen such annoying large
flies before. At three in the morning the sun was shining on top of the hillside.
In 1966, 300 miners were working in several levels underground. The ventilation engineer initially
escorted us down to the 2,000-foot level to explore the possibility of using that area to conduct our
measurements. My first impression of the place was negative. Ventilation was poor with
temperatures of 95 °F making it unsatisfactory place to work eight hours per day. While there we
felt uncomfortably warm. We had to remove our coveralls for relief. The next day, with all our test
gear we descended to the 800-foot level where miners were working in different locations with
adequate supply of fresh air forced into the elevator shaft and into different working areas. The
temperature and relative humidity in the working areas ranged from 40 ‒ 60 °F and 90 ‒ 95%
respectively. The mine was a wet mine in contrast to US mines in Colorado and New Mexico that
are rather dry. All underground transportation was via small electric trains. In 1967 when we
characterized uranium mine conditions in Colorado and New Mexico diesel equipment was used
throughout. The mine air in the Canadian mine was rather dust-free. However, one day when the
ventilation engineer was escorting us out of the working area he became lost and walked us
13
through an area they just finished blasting. The visibility was very poor due to residual blast
smoke. We navigated 800 meters through that harsh environment to reach the main drift at the base
of the elevator and the fresh air supply. The ventilation engineer was a novice who graduated from
college a few months earlier.
In another occasion five years later when I was testing and evaluating personnel WL monitors in
another Canadian mine at Elliot Lake, I experienced another incident that may have impacted my
health. The miners and I walked through a tunnel before we went underground. We walked
through the long tunnel to coat our lungs with a chemical intended to protect against silicosis.
Guess what happened three months later. After I returned back to New York from Elliot Lake I
came down with walking pneumonia. I spent three days in the hospital to treat the pneumonia that
left me very weak for another month before I was fully recovered. Here we are trying to control
exposure to radon and radon decay products and yours truly gets zapped by another routine
chemical miners breathe on a daily basis before entering the mine. Outside of these two incidents,
the Canadians were very good hosts and the most cooperative people I had the pleasure to work
with.
The results of the tests in the Canadian mine were very encouraging confirming the findings we
observed in the laboratory in New York and some other small mines in the U.S. We found
dependence of respiratory deposition on tidal volume. Total deposition was found to be a function
of particle size. The average total respiratory deposition for four subjects ranged from 23.0% 32.0% Nasal deposition of attached and unattached radon decay products were found to be about
1.3% - 2.0 % and 61.0 respectively. From the electric mobility measurements we found that about
20% of the radon decay products were neutral. In laboratory measurements I found about 25% of
the radon decay products were neutral. The first major study in a working mine was very useful in
terms of what kind of instruments we should upgrade or even go back to the drawing board and
develop new ones.
Now I’d like to turn our attention to uranium mining in the US. In 1954 there were 915
uranium miners. With the high demand for uranium, the number of miners reached 4,900. After
1961 employment in uranium mines declined as a consequence of curtailed government purchase
of refined uranium ore. In 1966 the number of miners went down to 2,545.
The US Public health Service conducted an epidemiological study in the early 1960s to identify
possible etiological agents for the high incidence of lung cancer observed among uranium miners.
The study found an association between exposure to RDP and a higher than expected incidence of
lung cancer when the cumulative exposure was more than 1,000 WLM. The findings were
reported by Duncan Holaday when he testified at the Joint Committee on Atomic Energy Hearings
in Washington on May 1967.
From 1965 to the present day I was well aware of the uranium activities because I was very much
involved in it for almost 48 years. However, in order to understand how we got here today we must
look back and see when the uranium frenzy began. The rush for uranium was triggered by the U.S.
desperation for domestic uranium. Ordinary Americans like in the earlier rush for gold took the
challenge to wrest riches from the earth.
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When Charlie Steen, a young Texan geologist, struck uranium in 1952, the race was on. Mining
companies both real and some bogus sprouted everywhere. As long as the U.S. government was
buying young men fresh out of college became instant millionaires. But no one could match
Charlie Steen’s talent and charismatic character. He gave millions of his uranium mining and
milling earnings to charities in every place he happened to live. The Utah Senate honored him as
an outstanding pioneer in the exploration and search for uranium. Charlie’s pioneering work and
his enthusiastic approach to new adventures was second to none. He made and lost millions and he
even declared bankruptcy while testing new ideas and mounting new adventures. I looked at his
life from many perspectives and I found him to be a curious adventurer, a kindred and generous
spirit. You can learn more about this unique and unusual explorer in the book “Uranium Frenzy
Boom and Bust on the Colorado Plateau” by Raye C. Ringholtz.
The Moab’s “Time Independent” wrote the following ballad to Charlie Steen.
Charlie-Charlie Steen
King of Uranium
Went to school at Texas mines
The Professor said, you might as well resign
So he packed his gear, and off he come
To find that yella stuff and stake his claim
Charlie-Charlie Steen
King of uranium
He went out hunting –every day
Ate rabbit stew and that ain’t hay
Finally his Geiger went bizerk
And now old Charlie’s richer than a Turk
Charlie-Charlie Steen
King of Uranium.
While the search or uranium was heating up, very few people became concerned about the
warnings of the radiation exposure of miners. The problems within the mines were ignored and
dismissed. In 1964 Dr. Geno Saccomanno performed an autopsy on Tex Garner who worked for
twenty five years in the mines and mills. Tex Garner came down with oat cell type carcinoma of
the lung and abundant tumor tissue in the liver, spleen and adrenal glands. Further analysis of body
tissues by Victor Archer showed large amounts of Po-210 and Pb-210. Garner’s exposure was
estimated at 1,870 WLM. Stewart Udall called the period from 1952-1967 a shameful period of an
atomic–age tragedy that could have been avoided. Duncan Holaday (who I met on many occasions
in the 1960’s) was the lead investigator in the Public Health Service on the prevailing working
conditions in the mines. He presented some bad news on the status of fifty miners who were
identified as dying from lung cancer. He warned the mining companies and AEC that underground
uranium miners are subject to lung cancer and urged that stepped up ventilation systems would
virtually eliminate the risk of radiation exposure.
In 1957, Holaday recommended an exposure standard for miners of 1 WLM. In 1967, the secretary
of labor Willard Wirtz under pressure by the labor movement suggested 0.3 WLM but under
pressure from the mining companies and AEC had to go back to 1 WLM. After considerable
discussions by consultants and experts such as Robley Evans, Karl Z. Morgan and Keith Schiager.
15
(I met all three) they reached a compromise for a Standard of 0.75 WLM.
After the hearings before the Congressional Subcommittee on Research, Development and
Radiation of the Joint Committee on Atomic Energy in May 1967, the AEC asked HASL to
investigate the radiological characteristics of uranium mine atmospheres. We were just winding
down our studies in the Canadian mine when the new assignment arrived from Washington.
In the Fall and Winter of 1967-68, HASL personnel aided materially by the AEC Office in Grand
Junction Colorado and by the US Bureau of Mines in Denver made plans to go out West in
working mines and find out what problems underground miners were facing. At the hearings the
most repeated request was to address the extreme variability of atmospheric characteristics within
a mine and among mines. In the laboratory in New York, the instrumentation division and the
machine shop devoted many weeks to upgrade our sampling and radiation measurement
instruments and fabricate more portable sampling equipment to be used by three HASL teams
during the characterization of uranium atmospheres. Since I spent the last two years on a full time
basis on radon studies both in the lab and in underground mines in Canada and the US, I trained
another eight hygienists and physicists to prepare them as part of the three teams that would be
going underground to investigate the conditions of exposure experienced by the miners.
Our first trip out West was in the Fall of 1967. Three teams of paired HASL employees sampled
and measured radon and radon decay products in different locations in three mines in Beaver
Mesa, Colorado three in the Uravan Belt, Colorado and in 1968 in three additional large uranium
mines in Ambrosia Lake near Grants New Mexico. Engineers from the Bureau of Mines provided
support by obtaining daily ventilation rates, temperature, relative humidity and barometric
pressure data. We selected locations in the mines to make sure we made our measurements where
miners worked. We spent 3-4 days in each mine. All of the mines were ventilated mechanically
with main fans located in shafts. Small booster fans connected to flexible ducts were deployed
underground to direct air to a specific location where the miner spent most of his time. Usually,
drifts constituted the primary route for ventilating air.
In the larger mines in New Mexico, the miner was responsible for extending the flexible duct with
fresh air close to his workstation. Unfortunately, in many situations the miner did not bother to do
that. He did not want to “waste” the time he could use to produce more ore and make big bucks. A
good productive miner was making as much as $50,000 a year in 1968 and thought very little about
his health being compromised.
When we investigated the mines in Colorado we stayed at the Court Motel in Grand Junction
Colorado. The motel rates were $5.00 per night. There were no television sets in the rooms but
there were plenty of restaurants and dining places for our meals. The drive from Grand Junction to
the mine areas was about 2 hours each way mostly on dirt roads carved at the edges of hills and
rocky formations. We rose about 5:00 AM every morning to have an early breakfast and take out
sandwiches for lunch.
One morning, while we were having our early breakfast at Gay Johnson’s Diner, one of our
teammates, a student from Drexel University who was doing his internship at HASL, ordered two
fried eggs, toast and coffee. He was allergic to potatoes and told the waitress no potatoes please.
Sure enough every breakfast plate had a portion of potatoes when served. Everyone was happy
16
with their meal except for our intern who became upset and scolded the waitress for serving
unwanted potatoes with his breakfast. The tired and sleepy waitress responded to him with no
apology and told him “Eat the eggs and leave the potatoes on the plate” That was hard to accept
and our young intern stormed out of the diner with a bag holding his take-out lunch.
Half-way to the mines and at the corner where we turned to drive uphill to the mining area there
was a small coffee stand that served the best donuts in the entire area. I believe it was called the
Gateway Café. With fresh coffee and donuts we drove another hour on dirt and dusty winding
roads to reach the mines. Measurements were obtained in at least seven locations per mine in
working areas where miners were doing tasks such as drilling, mucking and loading the blasted
ore, timbering and track laying. With the assistance of the mine engineers I was able to sketch all
the sampling locations that we included in the final report (HASL -220 1969). Average ore assays
were fairly uniform being in the range of 0.2-0.3% in all mines.
The average temperature and relative humidity ranged from 49-64 F and 62-90% respectively. The
ventilation rate ranged from 5,600 cfm in the smallest mines to 187,000 cfm in the largest mine.
Conditions of surfaces were mostly dry and motive power was pneumatic or electric in the small
mines in Colorado with mostly diesel in the large mines in New Mexico. Each HASL team was
equipped to measure the radon gas concentration simultaneously with the WL the equilibrium
ratio, ore dust concentration and external gamma radiation. The radon gas concentration was
measured with the Two-Filter tube method developed at HASL by Jess Thomas and Phil Leclare
The accuracy of the Two Filter method was established by comparisons with simultaneous
samples collected in Flasks that were sent to HASL in New York for analysis.
Isabel Fisenne the champion handler of the famous pulse ionization chambers did the analysis.
From 1981-2,000, the HASL pulse ionization chambers and the Radon Chamber served as the
Radon Standard Facility for the US and for most of the World.
The concentration of the individual radon decay products and the WL were measured with
scintillation alpha counters connected to strip chart recorders and were calculated using the
Tsivoglou Method as we did in the Canadian study. The precision of radon decay product
measurements were checked by comparing duplicate measurements. The precision as coefficient
of variation was about 10%.
Ore dust was collected on high efficiency filters for several hours at 20-25 liters /min. The filters
were later analyzed at HASL for total alpha activity after the radon decay products decayed. The
mean concentration of ore dust ranged from 1.7 - 12 a dpm/m3. The higher concentrations were
measured in relatively dry and dusty areas of the mines. Radon concentrations were found to be
independent of mining operations. They were more dependent on ventilation. Mine drifts with
higher ventilation rates showed the lowest radon and WL concentrations.
The highest radon levels were in stopes where ventilation was inadequate in most cases. When we
examined the WL monitoring data obtained routinely by the mining companies we found them to
be lower by a factor of 2 - 3 from our measurements. For example, when we measured the WL near
a miner in a dead-end stope about 1000 feet away from the main drift we found it to be 2.0 WL.
The mine engineer collected a sample for the WL at the entrance of the stope and 1,000 feet from
the miner and recorded it as 0.7 WL. I believe, the study conducted by HASL revealed some of the
17
poor procedures used in the mines to get a good estimate of exposure. Gamma intensities were
measured with Geiger - Mueller survey instruments. The mean gamma radiation ranged from 0.2 0.7 mr/hr.
The great variability of radiological conditions claimed by several witnesses at the 1967
Congressional hearings was confirmed by the measurements we made in nine uranium mines. The
WL Ratio increased as a function of WL. Individual values of radon concentration were in the
range from 4.0 -7,000 pCi/L. The range of WLs was 0.01 -7.2. The findings of the 1967-68 study
and of a subsequent study in large mines in New Mexico in 1971 which included particle size
distributions, were used by the BEIR Committee to arrive at a dose conversion coefficient.
The actual hard work of collecting and analyzing air samples in the mines was done by my
colleagues Robert Epps, Ronald Fedore, and Evan Wasserman AEC interns from Drexell
University and Henry Franklin Larry Hinchliffe, Ronald Knuth, Peter Loysen, David Rimberg,
Martin Weinstein and yours truly. Alfred Breslin, the Director of the Health Protection
Engineering Division spent a lot of his time to coauthor the final report.
When I returned from the Uranium Studies on the Colorado Plateau and New Mexico, I helped my
youngest brother to plan and prepare for his vacation back in Cyprus where my parents were still
living. My youngest brother Soterios, a single 23 year old auto mechanic was planning to visit
Cyprus to find the local village girl he knew five years earlier and possibly marry her and return to
the US as married couple. In October 1967, I drove him to JFK airport in New York to take a
British Airways flight to London and from there transfer to a British European Airways flight for
Athens Greece with final destination Nicosia Cyprus. On October 12, the BEA air plane departed
Athens for Cyprus. Unfortunately, someone planted a plastic explosive device on the airplane that
exploded about 100 miles from Cyprus resulting in the loss of 70 passengers and crew. On October
13, my brothers Constantine, Renos, Polyvios and I we left JFK airport for Cyprus and then flew to
the island of Rhoads to search for my brother’s body among the 40 bodies recovered from the
wreckage area near Rhoads. Unfortunately his body and that of the crew in the front section of the
plane was never found or recovered. It sunk 8,000 feet at the bottom of the sea. It was very tough
time for my mother not been able to see her youngest son ever again. She never recovered from the
loss of my youngest brother. In 1974 my brothers and I, we welcomed my parents back to New
York to live near us to help ease their pain and sorrow. They lived another 17 and 19 years in New
York. They passed on in 1991 and 1993 and were buried in Flushing cemetery in a family plot 300
feet from the tomb of Louis Armstrong and his wife Lucille. I believe Louis Armstrong was born
on July 4 1900. My father was born July 11, 1900. Born in places thousands miles apart and
forever resting within 300 feet from each other.
Between the trips in the mines in Colorado and New Mexico in 1967-68, HASL was working
feverishly to develop and improve sampling and measurement equipment to better characterize the
size distribution of radon decay products. Of primary importance was to develop a device to
measure the unattached fraction of radon decay products. In consultation with Professor Thomas
Mercer at the University of Rochester, I was able to design and have the machine shop to fabricate
a prototype small diffuser sampler that had high collection efficiency for unattached radon decay
products. I tested the device in the laboratory and I was confident that it should work similarly in
the mine environment. Another addition to our instrumentation arsenal was the development of the
18
first diffusion battery to be used in the laboratory and in the uranium mines for the measurement of
the particle size of inhaled radon decay products. The battery consisted of three separate sections
with widely differing collection efficiencies. At a flow rate of 2.0 L/min. their respective collection
efficiencies for particles of 0.05 microns, were 21%, 49% and 82% respectively. A second set of
the same diffusion batteries were used in the summer of 1969 to measure the particle size
distribution of the exhaled air in a small active uranium mine near Naturita, Colorado. We selected
7 locations for our study beginning near the ventilating air inlet and continuing along the main air
course to the point of discharge. This was done to get progressively changing environmental
conditions from location 1 to location 7 near the air exhaust point. For the radon gas measurements
we used the Two Filter method and the Tsivoglou and the Kusnetz methods for the measurement
of individual radon decay product concentrations and the WL. For particle concentrations we used
the portable Gardner small particle detector. For total respiratory deposition we used the method I
first used in the laboratory and in the Canadian study. Nasal deposition was measured at a flow rate
of 12.5 L/min.
The radon concentrations were 5-10 pCi/L at location 1 (with fresh air) and 2,000 pCi/L (1.4 WL)
at location 7 (exhaust air). The corresponding particle concentrations were 2,000 particles/cc and
84,000 particles/cc. Total respiratory deposition was similar to the laboratory and the Canadian
study showing total deposition as a function of tidal volume.
Total deposition ranged from 26% - 27% near the air exhaust area (aged air and high particle
concentration) and 34 -49% near the fresh air (with low particle concentration. Nasal deposition
measured in one subject (yours truly) measured at four locations averaged about 20%. In the lab
for the same subject the average nasal deposition was 6% reflecting the two different atmospheres.
The particle size data show that 70-90% of the radon decay products are >0.1microns. The
unattached fraction of radon decay products ranged from 0.8 - 3.5% except for location 1 and 2
near the fresh air inlet with low particle concentration that was 13%.
As previously, we found an inverse relationship between the unattached fraction and the
concentration of condensation nuclei (particle concentration) a relationship predictable on
theoretical grounds.
Larry Hinchliffe accompanied me in all the studies conducted by HASL in underground uranium
mines. His work ethic and help was essential in getting the work done. Most of our measurements
and counting procedures were conducted manually. Larry and Robert Epps an intern from Drexel
University handled all the computer work back at the laboratory for finalizing our report. Our
success in this mine was made possible by the great cooperation and assistance we received from
T. J. Shepich of the US Bureau of Mines, Denver. He made sure we were operating in a safe
environment.
Increased energy demand and global climate change concerns led to an expansion in nuclear
power generation. In 2010 there were 437 nuclear power plants worldwide with another 56 under
construction, 100 planned for construction and 270 proposed. Because of these demands, the need
for uranium mining was getting revived. In 2003, uranium was $10 per pound surging to $130 per
pound in 2007. In the US uranium mining ceased in the 1980’s due to significant stockpiles and
low prices. However, the increase in price after 2003 has stimulated developers to return to
19
uranium mining in Arizona, Colorado, Texas and Utah. I hope this time all the radiation safety
criteria are enforced and followed to prevent unnecessary exposure to the modern miners.
The period from 1969 to 1972 was a time for innovation for HASL. Jess Thomas developed a
new method called the Modified Tsivoglou method for determining the concentration of the
individual concentrations of radon decay products. Today this method and its extensions are used
in research situations throughout the world. At the same time Otto Raabe and M. Wrenn developed
the least squares method to fulfill the same purpose. The Raabe method determines the
concentration of Po-218 more accurately and can be very useful when determining the size
distribution of the individual radon decay products.
Although, the Mercer diffusion sampler for the measurement of unattached radon decay
products was found to be accurate and reliable for field application I evaluated and calibrated a
simpler technique for the harsh conditions in uranium mines. I found that unattached radon decay
products (mostly Po-218) can be easily collected by a single 60 mesh wire screen. The collection
efficiencies at air flows of 2 and 3 Liters/minute were 60% and 47% respectively.
HASL undertook a comprehensive program of measurements of radon concentrations and particle
size distributions at more than forty locations in New Mexico uranium mines. As a result of these
new developments, conditions in uranium mines became better understood, a significant
contribution to the needed research in this area.
The concern about radon exposure in Central Florida resulting from phosphate rock mining,
prompted HASL to investigate its impact on the general public and on the phosphate mill workers.
The rock contains modest concentrations of the uranium series. At one time the AEC considered
mining the phosphates for uranium but the availability of uranium from other sources and places
became cheaper and feasible and gave up the idea. Measurements made in several homes in
Central Florida showed low concentrations of radon. The fact that there were no basements in the
homes may be the main reason. Also most of these homes had windows open most of the time in
February when we conducted the measurements.
Measurements in the phosphate mills were even lower than those in single-family homes.
The phosphate mill plants were very large with high ventilation rates and had large windows that
were left open most of the time. However, more recent measurements in Florida even with no
basements, the number of houses with radon >4 pCi/L, is 13%. At about the same time, we made
radon measurements in homes in Eastern Tennessee located on Caunasauga shale and found no
elevated radon concentrations.
In the 1967 Congressional hearings on radiation exposure of uranium miners, it was concluded
that better techniques were needed to supplement or replace the grab sampling method used by
uranium mining companies to assess the radon and radon decay exposure of miners. Several
organizations undertook the development of dosimeters that could be utilized routinely in
underground mines. Film badges, alpha track detectors and thermoluminescence dosimeters were
developed and tested. These devices performed with varying degrees of success in the laboratory.
But, invariably, they failed to function reliably when tested in uranium mines under conditions of
actual use. Colorado State University and HASL did most of this pioneering work. At HASL, Otto
White was assigned to develop a method by which the monthly or quarterly exposure of uranium
20
miners can be measured. Otto, with help of several HASL employees made several trips to
uranium mines to test the WL integrating instrumentation worn by the miners while working. My
role in this effort was to be the Radiation Safety Officer (RSO) for the HASL employees and be
part of one team that tested the dosimeter making WL measurements near the miner and later
co-author the final report.
The HASL method involved the collection of mine air through a filter detector assembly
containing a 0.8 micron pore size membrane filter and 1/8 x 1/8 inch lithium fluorite chip
supported at 2.0 mm in front of the filter. During sampling, the lithium fluoride chip stores energy
from Po-218 and Po-214 that are continuously filtered from the air.
The pump-battery pack was connected to the dosimeter by a plastic hose. The dosimeter is
mounted underneath the brim at one side of the miner’s hard-hat where it is exposed to the
breathing zone. The pump was making a pulsating noise that annoyed the miners and when not
watched they removed the whole personal dosimeter and placed it nearby as an area monitor. Also,
some dosimeters exhibited moderate to serious malfunctions.
Both the HASL and the Colorado State University methods were eventually abandoned until
HASL later in 1976 used the modified lithium fluoride thermoluminescence dosimeter that was
developed in 1971 but with a new pump that maintained constant flow over a wide range of filter
loading.
With the acquisition of three new diffusion batteries designed by David Sinclair (Upton
Sinclair’s son) we were preparing to measure the particle size distribution of New York City room
air. The goal was to measure both the size distributions of condensation nuclei (inert particles) and
radon decay products (radioactive particles) in room air. The measurements were to provide
information on the attachment of radon decay products on the larger diameter particles
(condensation nuclei). The effective length of each battery was 18,400 cm, 115,000 cm and
295,000 cm respectively. The results of measurements that I made in November and December of
1972 showed the following. The concentration of condensation nuclei ranged from 52,000 –
100,000 particles/cc. The median diameter of the condensation nuclei ranged from 0.045 – 0.068
microns and the activity median diameter of radon decay products ranged from 0.100 – 0.133
microns. This was an important finding indicating the preferential attachment of radon decay
products to the larger particles in air.
HASL, was invited by the organizers of the Second Symposium on the Natural Radiation
Environment to characterize the particle size distribution of indoor and outdoor air in New York
City and report the findings at the meeting in Texas in 1973. So here I go again. I recruited my right
hand man Larry Hinchliffe to assist me in this effort. Together with a couple of student interns, we
made a number of measurements in the basement of the HASL building that had slightly elevated
radon and in the main corridor of the 5th floor of the same building where HASL is located The
basement location may be atypical because of the suspected leakage of radon from a nearby
storage facility. The outdoor environments were at street level at HASL and at ground level at a
rural environment at Sterling Forest about 50 miles north of Manhattan.
For indoor radon measurements we used a large volume two-filter tube and one-liter glass flasks to
collect radon at street level and at the rural location and perform the analysis at HASL in the pulse
21
ionization chambers. The concentration of individual radon decay products and the WL were
determined by the Thomas method developed by Jess Thomas at HASL.
The uncombined fraction of radon decay products was determined with a new device the new
method developed at HASL and tested by L. Hinchliffe and myself in a uranium mine atmosphere.
The device consisted of an 8.5 cm diameter 60 mesh wire screen. At a linear velocity of 17 cm/sec
had an efficiency of 47% for uncombined radon decay products. Particle size was determined with
the new diffusion batteries described earlier. The concentration of condensation nuclei was
measured with the Environment One Continuous Particle Monitor, Model Rich 100.
The summary of the measurements in the different environments are listed in the table:
Radon
(pCi/L)
WL
HASL Basement
6.0
0.023
4.5
0.18
45K
Corridor 5th floor
0.26
0.001
7.0
0.11
48K
NYC Sidewalk
0.17
0.0007
4.7
ND
190K
Sterling Forest
0.21
0.0009
9.4
0.30
7.7K
Location
Unatt. %
Part.diam.(µm)
Cond. Nuclei/cc
The activity median diameters ranged from 0.1 to 0.3 microns in agreement found later by other
investigators. The highest unattached fraction was found at the rural area where the particles in air
ranged between 5K to 12K/cc. The attachment coefficient at sterling forest appears to be about six
times greater than in the HASL basement.
As in previous studies I like to acknowledge the assistance of Robert Sladowski and George
Buckleman student trainees from Pratt Institute, New York, in making and processing the data
using primitive computer equipment. The findings of this study were reported at the Second
International Symposium on the Natural Radiation Environment in Houston Texas in 1972.
The First Symposium was held at Rice University in Houston Texas in 1963. I missed that
Symposium because it was held two month before my AEC security clearance was finalized.
However, I am happy to say that I participated in all the Symposia that were held every 5-7 years.
The last one was the 8th Symposium held in Rio, Brazil in 2007.
In 2002, I was asked to write a paper about the Historical Development of Natural Radiation
Environment (NRE) Symposia which I presented at the Seventh International Symposium on the
Natural Radiation Environment in Rhodes, Greece in May 2002. The reader can get a pretty good
idea how these symposia began and see the increased interest in radon from 1963 through 2002.
The next Symposium will be hosted by the Japanese in 2013 or 2014 but with the Fukushima
disaster its fate is unknown.
It will be fitting to describe how the Symposia began and who was responsible for getting them
started. The idea for a Natural Radiation Environment (NRE) Symposium was born in the Health
22
and Safety Laboratory (HASL) of the US AEC and in the department of Geology of Rice
University, Houston Texas. Important data regarding natural radiation were scattered throughout
the literature of a number of science disciplines making access difficult. The organizers of the
Symposia decided to bring together scientists from different disciplines working on natural
radiation to interact as a unified source of information that could provide the tools and data to
assess quantitatively the significance of additional radiation exposure from man-made sources.
They saw the need for an International Forum that would bring some coherence to the scattered
research and data. Natural radiation is an important subject not only as a fascinating area of
scientific inquiry but because the information that evolves from such an investigation provides the
perspective needed to evaluate the significance of the various levels and types of ionizing radiation
exposure encountered when using nuclear energy. The concern about radon became global and the
bulk of the papers at the Symposia and workshops on the NRE, were related to radon and radon
decay products.
Since 1963, after the First Symposium, thousands of papers on radon were published in scientific
journals and in laboratory reports. In the First Symposium only 10 papers were on radon. In the
Second Symposium out of 55 papers 12 were related to radon. I was one of the presenters on the
characterization of the radon decay particle size distributions in indoor and outdoor New York
City air.
Between the Second and the Third symposia, HASL organized two informal workshops in New
York on the Natural Radiation Environment in 1972 and 1974 respectively. HASL by now had
several scientists working on radon and acquired the expertise, instrumentation and research
facilities to host workshops of this type. Both workshops provided a Forum to identify areas of
further research and set the stage for the development of cooperative research programs for
information exchange. Most US laboratories conducting studies in environmental radiation were
represented at both workshops.
In 1975, the First Special International Mini-Symposium on (NRE) was held in Pocos de Caldas,
Brazil where more than ninety scientists discussed a wide range of geological radioactive
anomalies. A Workshop on Methods for measuring Radiation in and around uranium mills was
held in Albuquerque, New Mexico. A total of 33 papers were presented or radon related issues. I
presented and published three papers in the proceedings of the meeting.
In Febuary 1977, HASL was asked to organize and host a third workshop on studies of the natural
environment. Alfred Breslin and I drew a list of participants that were doing some work on radon
in the US and Canada and in research institutes. The theme was radon with emphasis on methods
of measuring radon and RDP and the application of those methods in investigations of normal and
enhanced radon exposures. The topic was mainly on metrology. The presenters were chosen for
their direct interest in environmental radon investigations and for having special competence in
radon monitoring techniques. There were 30 presentations; 8 from HASL, AEC
4 from EPA, 2 from the Bureau of Mines, 3 from Colorado Department of Health, 1 from Argon
National Laboratory, 4 from Canada and the remainder from several universities. The proceedings
of the workshop were published as HASL Report HASL-325, July 1977.
Now, I like to go back to address the conditions in uranium mines in the 1971-72 period. After
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the Congressional hearings in 1967, HASL undertook the characterization of uranium mine
atmospheres. In 1967-68, HASL personnel investigated mainly the conditions of radon and WL
concentrations and the ventilation patterns in working mines in Colorado and New Mexico.
However, information was needed on the site and the amount of deposition of radon decay
products in the respiratory tract that are depended on the particle size of the carrier aerosol and on
the unattached fraction of radon decay products. This information would be vital in calculating the
dose to the lungs.
As of 1971, there were no field data addressing the particle issue in underground mines. The sparse
data on the activity size distribution of radon decay products were subject to question because of
problems in analyzing the data. With the development and evaluation of the diffusion batteries, a
special cascade impactor and devices that determine the unattached radon decay products we were
able to measure them outdoors, indoors and in uranium mines. We found that the median diameters
of aerosols carrying radon decay products in typical mine environments were larger than
previously assumed. After we tested all the field equipment in the laboratory at HASL we were
ready to venture into the large and active uranium mines in New Mexico to characterize the
particle size distributions of radon decay products. Particle sizes around 0.01-0.2 microns in
diameter are particularly difficult to measure but with the combined use of diffusion batteries, a
special cascade impactor and a device that measures the unattached fraction we were confident
that it was possible to characterize the full spectrum of the radioactive aerosol. On this excursion to
the South West our destination was Grants New Mexico and the uranium mines nearby.
I was fortunate to recruit Larry Hinchliiffe who went along with me on other trips to the mines and
experienced the harsh conditions one has to work under while following the miner to investigate
the conditions of his exposure. Robert Sladowski a student intern from Pratt Institute and a
computer wiz was my third team member.
I believe the success of our venture into these mines was the combined effort of a perfect team
"The A-Team". Initially, we tested all our sampling and counting equipment indoors and outdoors
at HASL. Please remember that all our counting equipment was operated manually in those days.
We had to practice at the lab in handling the different instruments that were used simultaneously to
gather the information needed to characterize the mine atmospheres. Three of us had six hands
combined and we had to start and stop eight counters to count the samples simultaneously.
The concentration of radon was determined with the Two-filter method developed at HASL by
Thomas. The concentration of the individual radon decay products and the WL were calculated
from the Thomas method (modified Tsivoglou method). The Thomas method is more accurate
than the original Tsivoglou method because it uses longer counting intervals during the decay of
radon decay products collected on a filter. The unattached radon decay products were measured by
two methods using the HASL-1 diffusion sampler and the first stage of the cascade impactor. The
cascade impactor, borrowed from Tom Mercer at the University of Rochester consisted of seven
stages and a back-up filter. The first stage separates the unattached radon decay products. The
diffusion batteries, constructed at HASL, consisted of four units with different diffusion lengths
ranging from 5,000 cm to 373,000 cm (164 ft – 12,238 ft).
The aerosol concentration was measured during sampling with a portable condensation nucleus
24
counter. Usually, during a 10-minute sampling period for particle size measurements we measured
the aerosol concentration at least 7-10 times. Temperature and humidity was measured by the mine
engineer. The work activities in different locations in the mines consisted of drilling, blasting,
slushing, ore mucking, ore hauling and equipment maintenance.
The results of the study in 43 locations in four large uranium mines show the size distributions to
be log normal with activity median diameters ranging from 0.09 microns to 0.3 microns with a
mean value of 0.17 microns. These sizes were found to be greater than the sizes assumed by
various authors in calculating the dose to the respiratory tract.
When the BEIR committee met in California, I was invited to present the data on particle size
characteristics and the earlier data from the characterization of uranium mine atmospheres
(1967-68). I believe the committee used our uranium mine data to arrive at a conversion dose
coefficient after making some adjustment on particle growth in the respiratory tract.
The unattached fraction of radon decay products in all four mines had a median value of 3% and
mean of 4.0%. As in previous studies we found the inverse relationship between the unattached
fraction and particle concentration. In the fourth mine the unattached fraction were generally
higher being consistent with the lower particle concentration during periods of inactivity
The big lesson learned from this study was that the exposures in the four large mines were quite
different from earlier exposures since both the concentration of radon levels were found to be
lower and the type of airborne dust is different due to the heavy use of diesel equipment.
The activity median diameters were found to be as much as an-order of magnitude larger than
previously assumed in lung dose calculations.
In a previous trip to one of these mines to test the HASL-1 device for measuring the unattached
fraction of radon decay products, I was caught in a very hostile environment in a location where
the miner was mucking the ore with a huge diesel machine. Although these machines are equipped
with scrubbers to remove the carbon monoxide it appears the scrubber failed and the air the miner
and I were breathing was saturated with carbon monoxide. You could not smell it but the
suffocating effect and dizziness were signs that I should get the hell out of there as soon as my
10-minute sample for WL determination was finished. From that moment my concern for radon
dissipated. I guess all that comes with the job.
During the evaluation of the WL dosimeter, HASL saw the need for a more practical,
inexpensive and more sensitive device to measure environmental levels of radon. It has become
crucial to develop and upgrade practical scintillation cell detectors. The Lucas cell was too small
(0.1 liters) with a sensitivity of 0.5 cpm/pCi/L. Its use was limited in the field because it had to be
evacuated before sample collection. Also during evacuation the glass neck could easily break off
from the main metal body of the cell when connecting and disconnecting to the vacuum hose. My
goal was to address these weak features of the Lucas cells by developing a larger, more sensitive
and more durable device with two valves.
In 1973, the machine shop at HASL fabricated two prototype cells; a 165 ml and a 515 ml
cylindrical plastic flask with inlet and outlet metal valves for flow through or evacuation sampling.
The top plate cover of the flask was made removable for decontamination and recoating with zinc
25
sulfide silver activated phosphor. All internal surfaces of the flask including the photon window
were coated with fine powdered Dupont 1101 phosphor that allowed photon transmission to the
photo-multiplier tube. After calibration in the HASL radon chamber, the sensitivities of the two
HASL scintillation flasks were found to be 0.72 and 2.1 cpm/pCi/L respectively being 1.5 and 4
times greater than the Lucas cell.
The simplicity of the HASL scintillation flasks (cells) stimulated private organizations such as
Pylon Corp, Ludlum Instruments, EDA, Rocky Mountain and Eberline Corp. to manufacture
similar scintillation cells of different sizes.. At Eberline, they fabricated a 3.0 liter scintillation cell
that was used in their continuous radon monitor having the highest sensitivity of 6.0 cpm/pCi/L.
The late Bernie Cohen fabricated even a larger scintillation cell to be used at the University of
Pittsburgh radon project. I calibrated his large scintillation cell that proved to be too large for use in
the field. A paper describing the development of the HASL scintillation cells was presented by
yours truly at the Ninth Midyear topical symposium, Health Physics Society, Denver, CO (1976).
As my involvement in uranium mine studies was slowing down, I began to pay more attention
to radon concerns at AEC “excess sites” and in the indoor and outdoor environment. At HASL we
did not have the necessary instruments to measure time-average concentrations of radon.
Also there were no commercial instruments and methods that could speed up our involvement in
this new effort. Up to this time most of the radon measurements were made either by instantaneous
or grab sampling methods. I began to work on two devices mainly a modified two-filter tube that
could operate continuously for one week or longer.
The collected alpha RDP on the exit filter were detected by lithium fluoride chips that we used in
the late 1960’s while testing personnel dosimeters on uranium miners. The lower limit of detection
was about 0.05 pCi/L of radon in a period of one week.
The second device which I called the Passive Environmental Radon Monitor (PERM), measures
radon by collecting the Po-218 electrostatically on the negatively charged electrode in contact with
a lithium fluoride chip that detects continuously the alpha activity. Both devices after evaluation
and calibration were used in the lab, inside buildings, outside and around tailings piles.
The PERM devices were used extensively in the AEC ‘excess sites” in Canonsburg PA inside a
building with some radium contamination and outside in residential areas near the contaminated
site. I used them also in Lewiston NY to investigate the radon impact from a building that was used
as a storage depot for thorium and radium waste material. The windows and doors of the building
were broken and animals went in and out at all times. I hang some PERMs on trees for biweekly
radon measurements 1,000-2,000 feet from the storage area to see if there was an impact on the
natural background radon concentration. The whole area was isolated from the general public but
during the hunting season an enthusiastic hunter shot holes through a couple of my PERMs. He
must have used the hanging PERMS on trees to practice target shooting and hone his skills. The
study was successful and showed that the waste material in the neglected building had no effect on
the immediate surrounding area. If the runoff water near the contaminated site was impacted by
thorium and radium was not addressed as I did not collect water samples for analysis.
I also conducted a radiological survey at the Middlesex Sampling Plant in Middlesex, NJ. The
26
building was mostly vacant. The Coast Guard was using it occasionally. The radon levels inside
the large building were <4 pCi/L. Later, I made radon measurements in 15 residential buildings
near the site. The instruments that I just described were publicized and published in the
proceedings of the Workshop on Methods for Measuring Radiation in and Around Uranium Mills
Vol 3, No: 9, August 1977. The PERM later was copied by private companies. The Japanese
manufactured a modified version of it.
Besides the PERMs, HASL developed the first WL monitor that incorporated the lithium
fluoride dosimeter that we used in the late 1960’s in uranium mines. Emphasis was placed on the
shielding the pump to reduce the noise level while operating in residential buildings. The pump
was wrapped in lead to muzzle the noise when used in residential buildings. By adding a power
supply and a running time meter we came up with the time integrating WL monitor. There was no
need for an air flow meter because the pump maintained a constant flow of 100 ml/min. After
calibration in the HASL radon chamber it showed an LLD of 0.0005 WL in a week long measuring
period.
The WL monitor and the PERMs were used in an International study to obtain simultaneous
measurements of radon and WL at the Geothermal Region of Lardedello, Italy. In cooperation
with G. Scandiffio we conducted bi-weekly measurements to measure the impact of radon and
RDP from the use of geothermal energy. The report of the distribution of radon and radon
daughters in the geothermal region of Lardedello, Italy was presented at the Second DOE-ENEL
Workshop for Research in Geothermal Energy and was published in Report LBL-1155 (1981).
Additional measurements at the AEC “excess sites” were undertaken by private groups allowing
us to redirect our efforts towards measurements of radon and RDP in the indoor and outdoor
environment. Most of the instruments that HASL developed for the uranium mine studies were
modified to measure the lower concentrations of radon and RDP found outside of underground
mines.
One of the recommendations of the 1967 Congressional hearings on Radiation Exposure of
Uranium Miners was to find better techniques to supplement or replace the grab sampling method.
Our laboratory and some universities undertook the development of dosimeters that could be
utilized routinely in uranium mines. The HASL dosimeter that was developed and tested in the late
1960’s worked well in the lab and in simulated extreme mine atmospheres but failed to function
reliably in uranium mines under conditions of actual use. The proportion of malfunctioning units
was unacceptably high and remedial design changes have to be made. The pressure was on HASL
to work on a modified version taking into consideration what parts of the dosimeter needed to be
modified. The modified WL dosimeter consisted of two separate components, a sampling head and
a pump-battery pack connected to the head by a plastic hose. The sampling head was mounted
underneath the brim of the miner’s helmet to protect it from the worst of the water and mud used or
generated by the miner while drilling or mucking. The new and lighter pump was suspended from
the miner’s belt. Detection was by an1/8 x 1/8 inch alpha sensitive thermoluminescent LiF chips.
The chip stores energy from Po-218 and Po-214 that are continuously filtered from the air at a
sampling rate of 90 ml/min. The new pump maintained essentially constant flow over a wide range
of filter loading. Also, special attention was directed towards the mechanical design to overcome
the effects of dirt, corrosion and mechanical abuse that we observed in the previously tested
dosimeters. The pump operated for ten hours between battery charges. At the end of a shift, the
27
miner charged his pump overnight in a specially designed charging rack.
The new WL dosimeter was calibrated under conditions of humidity ranging from 35% to 95% and
at low and high dust loading. The performance of the pump was very good under the
aforementioned conditions that prompted us to proceed and subject the WL dosimeter to a series of
five mine tests in a mine at Elliot Lake, Ontario of varying length from two weeks to several
months for a period of five years. I like to acknowledge the important cooperation and contribution
from Reub Yourt who provided information on mine conditions during tests which he conducted
in the Canadian mine. The initial tests in the Canadian mine I conducted myself along with one of
our college interns.
In the mine tests, dosimeters were provided to miners to represent different mining activities and
levels of exposure. Several miners were fitted with the new dosimeters and two HASL employees
followed them through their work shift making grab samples for the WL using the Kusnetz
method. We were making hourly measurements and sometimes more frequently measurements of
the WL. Any problems and deficiencies encountered in the initial testing were eliminated and the
dosimeters operated without difficulty throughout the last test period of five months in 1976. The
dosimeter showed some sensitivity to thoron daughters whereas the Kusnetz method of 5-10
minute sampling duration does not.
Some miners indicated that the pump weight of 1.0 kg, was excessive. This could possibly be
reduced using plastic instead of metal casing. The WL dosimeter although performed well in a
uranium mine, did not gain popularity among miners. Miners must be persuaded to tolerate some
amount of additional encumbrance. Another consideration is the additional cost to mine operators
and mining companies that will be reluctant to abandon the simple occasional grab sampling
methods. In the last 15 years, very little is been done to manufacture light-weight personnel WL
dosimeters. Since uranium mining ceased in the US in the late 1980’s, the Canadians undertook the
development of alpha track detector WL dosimeters for which I have no recent information. As I
mentioned earlier, after I returned to New York from Elliot Lake I came down with pneumonia
caused by a chemical sprayed in the tunnel leading to the elevator and underground. The miners
breathed the chemical to coat their lungs as a silicosis prevention measure. Unfortunately, this
chemical agent did not agree with my respiratory system.
While working on the development of the HASL WL dosimeters, I was asked to investigate the
performance of the Colorado State University WL monitor. People that used the monitor suspected
that it underestimated the WL. I secured two units to investigate their calibration and performance
under different conditions of particle concentration. I did find out that the unit was underestimating
the WL by a factor of two. The culprit was a pump inside the monitor that caused the plate-out of
RDP before they reached the filter detector assembly. My findings and recommendations were
published in a HASL Technical Memorandum TM-75-6, 1975
To provide accurate information on natural airborne radioactivity, we have been measuring
radon and related variables in the Metropolitan New York area for a number of years. I reported
the initial phase of our investigation in 1972 in the Natural Radiation Environment II. I obtained
detailed measurements on radon and RDP concentrations and on the physical characteristics of
RDP for periods of a few days at each of several indoor and outdoor locations. The findings of that
28
study convinced us that time-averaging instrumentation would be needed for systematic
monitoring of exposure.
After developing the suitable instrumentation, I began to make measurements for about 2 years
in 21 residential houses in New Jersey and New York. Although, I contemplated a pilot study to
test instruments and procedures it turned out to be the first radon survey in the US. I gathered
enough information to estimate average radon exposures and to ascertain the magnitude of the
possible sources of radon in these residential homes. The homes were chosen for accessibility.
They were the residences of laboratory staff and acquaintances. They were all within a radius of 35
miles from Manhattan and the Health and Safety Laboratory (HASL).
I like to call this 2-year study as a classic one because for the first time it addressed so many
parameters such as simultaneous radon and RDP concentrations on two or three floors (cellar, first
floor and second floor). Outdoor air also was measured in some cases. Diurnal variation was
examined in a few houses. To get a better estimate of dose, I measured the unattached fraction and
the particle size distribution of attached RDP in a few houses under representative conditions of
occupancy. The unattached fraction was measured with the wire screen technique and the size
distribution of the attached RDP was measured with high flow rate diffusion batteries described by
Sinclair, George and Knutson). In most of the houses, I measured radon exhalation from the cellar
floors, the radium content of soil and radon in water to acquire information on sources of radon.
This was one of the first studies of its kind and it has been used as a model by other researchers.
The radium content in soils near 18 houses ranged from 0.8 –1.5 pCi/g with an average value of 1.0
pCi/g. This is assumed to be the normal background. The radon flux from cellar floors ranged from
0.8 –18.0 aCi/cm2/sec with an average of 6.5 aCi/cm2/sec. The highest value was measured in
Morristown NJ.
Radon in water in all 21 homes ranged from 10 –1,400 pCi/L. The highest value was measured in
a New Jersey home that uses well water. Most of the houses in the study use water from reservoirs
or lakes. The geometric mean distribution of the annual radon concentrations in the cellar and first
floor were found to be 1.7 pCi/L and 0.83 pCi/L. Outdoors annual geometric mean distribution
were 0.18 pCi/L. The geometric distribution of the mean WL concentrations in the cellars and the
first floors were found to be 0.008 WL and 0.004 WL respectively. The mean concentrations of
radon on the first floor was one-half of the cellar radon concentration and the outside radon
concentration was about one-fifth of the first floor concentration. The first floor WL was one-half
of the cellar WL, and the outside WL four-tenths of the first floor WL. The WL on the first and
second floor was essentially the same. The WL ratios ranged from 0.3 – 0.7 with an average 0.5 the
value EPA later recommended to convert the radon concentration to WL.
From measurements of particle size in four residences, the average activity median diameters for
the attached and unattached fractions were 0.125 microns and 0.007 microns respectively. The
magnitude of the unattached fractions obtained with the diffusion batteries was confirmed by the
independent measurements with the wire screen technique. The annual absorbed dose to the basal
cells in millirads was calculated using N. Harley's dosimetric model equation:
Annual absorbed dose (millirads) = 42 CRn + 25,000 WL
29
where CRn is the annual mean concentration of radon in pCi/L and WL is the annual mean
working level. Assuming the unattached fraction is 7%, the annual mean doses ranged from 120 420 millirads in the cellars of New Jersey homes. In New York cellars the annual dose ranged from
60 -190 millirads. The dose in five New York homes on the first or second floor ranged from 40
-110 millirad. On the average, exposures in New Jersey residences exceeded exposures in New
York residences by a factor of 2.5. Based on the small number of homes in this study we cannot
generalize for the entire housing stock in the US. One thing we found for sure is that as we move
west of the Hudson River into New Jersey we begin to see a different radon profile from that of
Manhattan and Long Island.
When the Stanley Watras home in Pennsylvania was found to have 2,700 pCi/L of radon, EPA
took the radon problem seriously and began to address the problem by conducting the National
Radon Survey that marked the beginning of an entire new radon industry. Also some States began
to conduct their own radon surveys providing more information on regional basis.
The Third NRE Symposium was held on Aprill 23-28, 1978 in Houston Texas. The principal
sponsors of the Symposium were HASL, US DOE and the University of Texas School of Public
Health. Since our lab was one of the organizers I was asked to present my findings from the radon
study conducted in the NY Metropolitan area. The title of my paper was the distribution of ambient
radon and RDP in residential buildings in the New Jersey –New York area. My findings that I
discussed earlier were published in the proceedings of the Symposium.
The growing interest on radon was reflected by the number of presentations. Of the 108
presentations half of them were on radon and RDP. Many participants from 20 countries gathered
in Houston. The Europeans presented papers on radon recognizing the importance of radon as
worldwide health problem. More than 50 papers on radon were presented and published in two
volumes totaling 2,736 pages. At the same time, radon was becoming a topic of interest worldwide
before the Stanley Watras incident and the beginning of the EPA takeover of the radon program
from DOE and the beginning of the radon industry as we know it today. One evening, the meeting
hosts gave the participants an outdoor barbeque feast with margarita drinks served in large water
glasses. I can tell you from personal observation that some of the participants felt very gay by the
time the party was over. My advice is to watch out from drinks made with the powerful Tequila
served in water size glasses.
The four carbon diffusion batteries were developed to sample RDP particles at higher
Flow rates specifically in places with environmental levels of RDP (Sinclair, George
and Knutson). Once tested at HASL, we used them in an inter-comparison study in Socorro, NM.
Professor Marvin Wilkening from the University of Socorro, NM invited Earl Knutson and myself
to inter-compare methods and techniques used by the two groups.
The HASL 515 ml scintillation cells were used to measure radon and the carbon diffusion batteries
at an air flow rate of 280 L/min were used for the size distribution of RDP. To resolve the size
distribution of RDP, we utilized the Twomey nonlinear iterative algorithm using the measured WL
penetrating each diffusion battery. The Socorro group measured RDP concentrations at an air flow
rate of 700 L/min. Good WL agreement was found by the two groups. The activity median
diameter of the major mode outdoors ranged from 0.068 – 0.113 microns nanometers comprising
90% of the total RDP activity. The remainder 10% of the activity was associated with the minor
30
mode or the unattached fraction. The particle concentrations were in the range of
12,000-22,000 particles/cc. Inside rooms 10 and 108 the activity median diameter of the major
mode ranged from 0.080 – 0.087 microns comprising about 86% of the total RDP activity.
The particle concentration ranged from 15,000-55,000 particles/cc. The size distributions in a
tunnel showed an average activity median diameter of the major mode of 0.113 microns
comprising only about 50% of the total RPD activity. The particle concentration was 5,000
particles/cc showing that the unattached RDP fraction increases as the particle concentration
decreases.
I’d like to acknowledge the cooperation and assistance of Professor M. Wilkening and L. Andrews
who provided us with test locations and other logistical support. Their hospitality and involvement
made this study the success it was.
Radon flux measurements: In the mid 1970’s HASL was asked to conduct radon flux
measurements in Central Florida. At that time we did not have a practical and simple method for
use in the field. The only method that comes to mind was large 35 gallon drums turned upside
down into the soil for 24 hours and then collect a grab sample in a 165 ml HASL scintillation cell
for alpha counting. When I used this method I found it adequate but cumbersome for the
characterization of soil radon emanation studies on a large scale.
Richard Countess at HASL researched the literature and he had become convinced activated
carbon might be a suitable replacement for the can method. At Oak Ridge Tennessee there were
several thousands of excess M-11 Scot Air Pack charcoal canisters that we got hold of for Richard
to evaluate and calibrate them for measurement of radon flux from soil. The laboratory tests
proved successful and the M-11 canister became the HASL standard method for radon flux
measurements for a couple of years. Richard Cuntess, conducted a large and successful survey of
soil radon flux in Florida during different seasons. Using the same type charcoal canisters I
conducted radon flux measurements in Edgmont South Dakota on an AEC excess site.
During the development of the activated carbon method for measuring radon in air I used 4 –inch
charcoal canisters of the open face type to measure radon flux. I calibrated the new canister on the
HASL concrete slab that was spiked with a known amount of Radium 226. In the field, I used the
field station that HASL and later EML set up and maintained in Chester New Jersey. The canister
was sealed at the end of a 4-inch metal pipe. The open end of the 5-inch pipe was driven 1-inch into
the soil. Usually 24 hours were adequate to measure accurately the radon emanation rate. In radon
emanation studies using a small can we found that the radon concentration inside the can after 24
hours was becoming too high and the radon was getting pushed back into the soil. With the canister
method this problem is avoided because the radon is adsorbed by the activated carbon and does not
allow buildup in the 5-inch pipe.
The study in New Jersey throughout all seasons lasted 3 years. We found that radon emanation in
some cases varied by more than a factor of 10 when canisters were placed 4-6 inches from each
other. Today, when I get questions about making radon flux measurements and estimate how much
radon will get inside a home I respond by telling them “forget about it.” Because of the great
variation of radon emanation within a square foot area one must make hundreds of radon
emanation tests to get an average value. Imagine the cost and the consideration of all the other
31
factors that inhibit or allow radon to get inside a home. My recommendation to the callers is to use
radon resistance features to limit radon entry into the new home. During the winter time and
specifically the last two weeks in January and in the first two weeks in February when the top
couple inches of soil freezes the radon flux dropped by a factor of 20-30. The same effect was
observed when the soil is covered with ice. From personal experience I found out that radon flux
measurements are not useful except in characterizing contaminated sites.
In October 1980, the New York Times asked EML to make spot checks of radon levels in
seven below ground locations in Manhattan frequented by the public. The places were the
subway systems, Grand Central Station and the American Museum of Natural History. Photos of
Earl Knutson and myself performing the measurements made the Science Section of the New York
Times on October 7, 1980. In general the radon levels in subway platforms between Times Square
and the 8th Avenue Line were <0.5 pCi/L. The walls of the tunnels are made with thick concrete
covered with tiles that essentially seal the radon in the soil. Also the ventilation in the tunnels is
quite good and the air in them is exchanged with outdoor air through grid openings on the street
level. Remember Marilyn Monroe’s photograph where her dress was flowing upwards by the
subway tunnel exhaust air revealing her underwear when she stood on top of the grid opening on
the sidewalk on Lexington Avenue and 53rd Street. That picture from the movie the “Seven Year
Itch” became a classic. In the Grand Central Station with the massive granite construction and with
hundreds of people at any time we found very low radon concentration. The air exchange must
have been very high in this gigantic edifice.
In the subway platform of the Museum of Natural History, the radon level was about 0.5 pCi/L.
When I measured the radon in different floors of the Museum, I found radon levels <1.0 pCi/L.
The only place I measured radon above 10.0 pCi/L was on the 4th floor in the Precious Stones or
Gemology storage section. Besides the poor ventilation there were some uranium ore bearing
rocks that may have been the source of the airborne radon. I advised the personnel responsible for
that facility to increase the ventilation in that large room and consider a permanent fix.
After the radiological survey of the radium contaminated AEC sites, some concern was raised
by local government officials about the possible elevated radon levels in nearby residences in
Middlesex, NJ, Lewiston NY and Canonsburg PA. I was asked to conduct radon measurements in
15 homes in Middlesex, in 10 homes in Lewiston NY and in 8 homes in Canonsburg PA. The
buildings were primarily single-family homes volunteered by their owners. The study was for a
period of two years (1978-80). Using the PERMs that I described previously I conducted one or
two week-long radon measurements repeated several times over a period of two years. The
monitors provided by our laboratory were maintained in the field by the NJ DEP in Middlesex, by
the National Lead Co. of Ohio in Lewiston and by personnel from the Pennsylvania Bureau of
Radiological Health DER, in Canonsburg.
The annual average radon concentrations in Middlesex ranged from 0.32 – 0.95 pCi/L with a
geometric mean of 0.5 pCi/L. In Lewiston NY the annual average radon ranged from 0.32-0.79
pCi/L with a geometric mean of 0.52 pCi/L. In Canonsburg PA, the annual average ranged from
0.45-4.5 pCi/L with a geometric mean of 0.78 pCi/L that is slightly higher than the Middlesex and
Lewiston data. In one building in Canonsburg the annual average was 4.5 pCi/L.
The cellar walls in this building were badly cracked and water and soil possible sources of radon
32
infiltrated into the cellar proper when it rained. The radon levels measured indoors in 33 buildings
in the three diverse geographical regions were found to be consistent with measurements obtained
in buildings located far away from contaminated sites indicating that the contaminated sites had no
impact on the nearby residences. Many thanks to Janette Eng from the NJ DEP who worked very
closely with me during this study that resulted in a co-authored paper that was published in the
Health Physics Journal.
At about the same time, the N J Bureau of Radiation Protection was informed by EPA that there
was concern about the impact of radium waste material at the abandoned site in Orange NJ. This
prompted the NJ Department of Environmental Protection to seek assistance from EML to provide
instrumentation for conducting screening measurements for radon using grab sampling methods
and procedures developed by EML. I was assigned by EML to assist the state of NJ providing them
with large scintillation cells developed at HASL in the mid 1970’s.
Janette Eng of the NJ DEP as the key investigator collected grab samples in the scintillation cells
and returned them back to EML for analysis. The screening samples indicated some buildings
were highly contaminated.
The NJ DEP decided to conduct long-term measurements at least weekly or bi-weekly in duration
to better characterize the extent of the contamination. The NJ DEP requested
assistance from EML to provide integrating instruments for radon and radon decay products
(RDP). For radon measurements I provided NJ with PERMS (passive environmental radon
monitors) that I used previously in other projects associated with the AEC excess sites. The radon
detector was a thin alpha sensitive thermoluminescent LiF chip. For RDP measurements I
provided NJ with the modified EML dosimeter (MOD) in which air is sampled continuously for
one week to a month. The RDP Po-218 and Po-214 collected on the filter are detected by the LiF
chip positioned above the filter. All the instruments sent to NJ were described in the literature by
yours truly.
The integrated radon measurements in buildings B and C were 7.8 pCi/L and 10.0 pCi/L.
In building D radon levels as high as 28.0 pCi/l were measured. The concentration of RDPs were
also high indicating a contaminated site. In the warehouse the radon was as high as 56 pCi/L
almost twice the occupational level. In building A which was not part of the former radium
processing site radon averaged 3.1 pCi/L.
When NJ DEP requested EPA to conduct an aerial gamma survey of the area they found that 19
homes in the nearby towns of Glenn Ridge and Montclair were contaminated. New Jersey officials
believed that the contaminated soils in those houses might have been fill removed from the
grounds of the former US Radium Corporation in orange NJ. It was estimated that the radium
processing plant dumped about 1,600 tons of radioactive waste. Fortunately the EPA Superfund
took over the remediation of the whole area including the 19 residential houses. The contaminated
soil from the 19 homes was shipped to Utah. The entire cost covered by the Superfund was about
$240 million for investigation, waste disposal and construction in the entire site.
To support our findings on the size distribution of RDP, E. Knutson R. Knuth and myself made
measurements at EML using three different types and size diffusion batteries and two cascade
33
impactors. The inter-comparisons confirmed our previous findings that the RDP have usually
bimodal distributions with the major mode at about 0.1 micons. The minor mode appears to be
between 0.005 – 0.01 microns . The size of the minor mode appears to correlate with the age of the
Po-218. The impactors indicated that <15% of the RDP are larger than 0.6 microns in diameter.
EML Radon Inter-comparisons. In June 1980, we held a workshop at EML to discuss
the ongoing radon research and its future direction in studying the indoor environment. Fourteen
participants including a Canadian participant at the meeting recommended that there was a need
for inter-comparisons of the methods for measuring radon and RDP. In March 1981, we arranged a
follow up meeting at the Lawrence Berkeley Laboratory (LBL) for a second workshop with the
view toward establishing an inter-laboratory calibration network. EML, having set up a walk-in
radon calibration facility in 1964 offered to serve as the site for radon inter-comparisons on a
quarterly or semi-annual basis. It should be emphasized that Isabel Fisenne as the leader in the
maintenance and operation of the EML pulse ionization chambers was the key person in selecting
EML to host the inter-comparisons.
Isabel with Helen Keller and myself became the EML trio who conducted more than 30 National
and International radon inter-comparisons During the inter-comparison exercises the three of us
(Radon and the two Daughters) could be seen through the viewing window of the EML radon
chamber busy filling the participants radon collectors or setting their integrating or continuous
radon or RDP devices for evaluation or calibration purposes. EML developed the National radon
inter-comparison program and opened it to any group in the public or private sector that conducted
surveys or research on the indoor concentration of radon.
In the absence of a radon standard, calibration of instruments and methods ought to be based on a
laboratory standard derived from a NIST SRM Radium-226 solution. Well, EML offered the best
facility for that purpose. Even, the NBS (today NIST) depended on EML for their radon
measurements Quality Assurance in the early 1980’s. The EML pulse ionization chambers have
been rigorously calibrated five times between 1960 and 1984 using NIST SRM Radium-226
solutions and became the Radon Standard Laboratory worldwide. Everyone doing radon work
depended on EML as the primary facility for trace ability purposes. EML served in that capacity
until 2,000 when EPA assumed the role as a primary radon center and served the needs of the
radon industry. Over a 20-year period more than 50 groups or facilities took advantage of the
cost-free intercomparison exercises. Besides US participants the exercises after 1983 included
representative labs from Canada, Sweden, Germany, UK and Australia. EML, the Bureau of
Mines in the US and the NRPB in the UK and the Australian Radiation Lab (ARL), had become
the four reference laboratories
The First Radon Inter-comparison exercise was conducted in April 1981 to be followed by the
second one in June 1981. The EML pulse ionization chambers served as the radon standard for
every other method to be compared with. In addition, EML was one of the participants with
scintillation cells developed by yours truly. The other participants were the US Bureau of Mines,
US EPA Montgomery and Las Vegas, NBS, Mound Facility, Lawrence Berkeley Lab, Argonne
National Lab, New Mexico Tech Socorro NM, University of Texas and Oak Ridge National Lab.
As you can see there were not many private companies at the time. The major actors were some
universities and some National Labs.
34
All the participants sent scintillation cells to be filled at EML to be analyzed at their facilities and
then report their results to EML. The participant’s scintillation cells served as the standard method
used in their calibration facility if they had one. The results from these two inter-comparisons
indicated reasonable agreement at radon levels from 40-50 pCi/L. Most of the labs were within 5%
of the reference value. As the Radon Program was expanding the inter-comparison exercises
included a variety of instruments such as scintillation cells, activated carbon collectors of different
sizes and configurations, electret ion chambers, alpha track detectors and a variety of pulse
ionization chambers, solid state detectors from Sun Nuclear, NYU and the RAD-7 from MIT. I
believe free access to our facility benefited the new companies that were entering the radon
market. From 1980 through 1996 when I retired from DOE, I helped and consulted with many
instrument companies during the development of their instrument and methods for measuring
radon and RDP. Whenever we developed an instrument at DOE it was readily available for
everyone to be copied or be modified without any restrictions. DOE passed the technology free of
charge. Anyone that needed to evaluate, check and calibrate instruments or methods was
welcomed at all times. Personally, I was glad to accommodate everyone. It was a great period for
me as a radon ranger. I loved every moment of it. I met hundreds of people who came to EML from
1980-1986 at 376 Hudson Street five blocks north from the twin towers of the World Trade Center.
In the 1970’s several methods for measuring radon in air have been described.
In each case the method was designed to for a specific application, differing in concentration level,
required accuracy and sampling environment. From personal experience I noted that in most
instances, a single average concentration of radon over periods of days, weeks or months is
adequate to assess the radiation hazard to the occupants of buildings. To accomplish this, I began
to investigate simple integrating devices that can be used in place of more complex continuous
monitors that were to materialize in the 1980s-1990’s.
After extensive use of the M-11 charcoal canisters to measure radon flux from surfaces, I
evaluated and calibrated them and used them successfully to make integrating environmental
radon measurements over a period of 2-7 days. The original M-11 canister was developed by the
US Army Chemical Corps during World War II. It was rather large and in limited supply from Oak
Ridge Tennessee with variable gamma background. Canisters built before nuclear testing had
lower gamma background from those built between 1945-46. I began to look at alternate carbon
suppliers and smaller cans. The advantages of the charcoal canisters fabricated at EML DOE, were
substantial; simple, maintenance free, completely passive requiring no transfer of sample for
analysis adapted for recycling making the method low-cost and attractive for collection and
detection of radon. The initial canisters developed at EML including the M-11 were of the open
face type and performed successfully in different radon environments. In radon tests in the EML
chamber where the radon was varied intentionally by more than a factor of three the average radon
concentration obtained with charcoal canisters was within 1% from that recorded by a continuous
radon monitor. In a residential building with radon about 1.0 pCi/L, over an exposure period of 60
hours the canisters were found to measure radon within 2% of the continuous radon monitor. It
was very encouraging and reassuring that a simple and inexpensive technique produces accurate
measurements.
The calibration methods used by EML during the charcoal canister development were copied and
35
modified in some cases by numerous radon firms that developed their charcoal methods using
either canisters and bags with gamma counting or liquid scintillation methods using alpha and beta
counting. There is no registered patent for the charcoal method because I never applied for one.
The technology was readily available for anyone who was interested to adapt it.
Although the open face canister method was proven accurate for 2-7 exposures at humidity of
<70%, later I developed the diffusion barrier canister that was suitable for measuring radon even if
it varied by a factor of 10 during a 2-7 day exposure and at humidity ranging from 25%-95%.
The EML charcoal canisters were used extensively between 1979-1986 to measure radon in
different parts of the country. Charles Osterberg a DOE employee in Washington used them to
conduct a radon survey in Maryland and the Washington DC area. He was working with the
Damascus Maryland Energy Savers a group that was concerned with energy conservation. Yours
truly measured radon in 41 homes in the areas recommended by Dr. Osterberg. Each home was
tested twice in winter and summer to get a yearly average concentration. About 50% of the homes
were found at or above the value recommended by the National Council for Radiation Protection.
I believe this was the first study of its kind and a prelude to more studies throughout the country
and served as a field trial run for the newly developed technology.
As the charcoal canister method for measuring radon was becoming popular, I began to get some
publicity and recognition by my colleagues and other organizations. On December 14, 1984,
EML’s Award Committee presented me with the EML Workers Choice Award. The certificate
states the following.
The EML awards committee is pleased to present this certificate to:
Andreas George
For his proper handling of Radon’s daughters, we proclaim him “Father of the Year”.
36
Andy on his father, Christodoulus’ lap next to mother
Katerina and brothers Constantine and George
Reading the book The Machinery of the Body on army cot.
Trieste, 1953.
In army uniform chopping tree. Trieste, 1953.
37
Corporal Andy George in army dress uniform. Trieste, Italy. 1953.
Readying to fire a bazooka in Trieste, Italy.
38
Andy conducting radon decay product inhalation measurements of NYC indoor air. 1965.
Conducting radon decay product inhalation measurements in an
underground uranium mine. Colorado, 1971.
39
Checking instruments at the entrance of a walk-in uranium mine. Colorado, 1971.
Determining the size distribution of atmospheric radon decay
products with high volume diffusion samplers
40
Andy conducting radon decay product deposition on surfaces in the 20 cubic
meter radon chamber. 1976.
Andy and George Buckleman conduct outdoor radon and radon decay product
measurements in Sterling Forest, New York. 1976
41
Congratulated by U.S. DOE Secretary John Herrington after receiving the
Meritorious Service Award during ceremonies in Washington. January 13, 1987.
In lab coat, conducting radon and radon decay product intercomparison measurements
in the new EML radon chamber. Jim Short and Phil Jenkins from Bowser/Morner and
David Gray from EPA were regular participants in the late 1980s.
42
In the midst of the radon measurements in NJ, NY, PA NH and CT our European colleagues
and especially the Radon Rangers wanted to host a radon meeting in Europe. Instead of a
major NRE meeting, the Europeans were willing to host an International Seminar on Indoor
Exposure to Natural Radiation and Associated Risk Assessment in Capri, Italy.
The Seminar was organized by the CEC in Brussels, ENEA Italy and the US DOE. Wayne
Lowder, John and Naomi Harley, Earl Knutson and I were representing DOE. The Seminar
covered the implications of exposure to low radiation doses arising from indoor radon, thoron and
their decay products and from indoor gamma exposure. At that time the concern about radon
dominated the subject of natural radiation and brought together many "radon rangers" to the island
of Capri to share their experiences on the newly emerging indoor air pollutant. Representatives
from every country in Europe, Canada, the US, South America, Japan, India and Australia
gathered in beautiful Capri to share their radon stories
All 85 presentations were related to radon, a first of its kind. I can state emphatically that this
meeting was the most impressive one. It was an unforgettable gathering of early Radon Rangers.
The proceedings including the EML papers were published in the Journal of Radiation Protection
Dosimetry.
The local environment, the food and wine were excellent. I had calamari that was prepared in five
different ways. I even introduced my fellow colleague Earl Knudson from EML to Calamari. One
evening, our Italian hosts staged a dinner and show that lasted into the wee hours.
The music and plentiful wine put everybody in a good mood to have a good time. After dinner, I
heard singing by some scientists on their way back to their hotels. The melody in the tune of ''You
are my Sunshine” but in newly coined words around radon and radon daughters went like this:
You are my daughter,
my unattached daughter,
you make me measure
and I have fun
you will never know dear
how much you confused me
until we saw, one of you
was a son
Your mother is exhaling
into every space
and diffuses backwards
every now and then
You will never know dear
how much she confuses me
perhaps I should change
the charcoal again.
The next day I found the writer of the song to be none other than my friend Chris Samuelson from
Sweden. I can tell you that a lot of interesting work was accomplished at the Seminar without a
boring moment. I miss that international camaraderie terribly. It was one of a kind.
43
At the conclusion of the Seminar, three National Laboratories EML, NRPB and ARL spent one
week inter-comparing their methods for measuring radon and RDP at the walk-in radon chamber
at the National Radiation Protection Board (NRPB), Oxford, UK.
When the DOE asked EML to characterize the ore dust in uranium mills came to the right
place where Ron Knuth was working on impactors for many years. Ron and I went out West to
characterize the airborne activity and the respirable fraction in a uranium processing plant.
Activity median diameters ranged from 5 to 30 microns with a median diameter of 11 microns.
The maximum respirable fraction was <15%.
As part of a program to investigate the impact of energy conservation technology on the
indoor concentration of radon we began to measure radon, RDP and radon sources in different
localities. We wanted to find out if tightening a building leads to elevated levels of radon and other
indoor pollutants. At first we investigated 11 buildings that used solar energy in New Hampshire,
Connecticut, New York, New Jersey and New Mexico. These buildings represented the major
types of energy efficient solar structures. Integrating measurements for radon and RDP were
conducted over periods of 3-10 days during the cold months. Measurements in 14 locations
showed that 85% of them had radon <1.5 pCi/L. The radon in water in the buildings in New
Mexico supplied by local wells ranged from 360-575 pCi/L. In New Hampshire radon in water
supplied also by a local well was 9,000 pCi/L). In the other buildings supplied from surface water
sources radon was <25 pCi/L. The radon flux ranged from 3-10 aCi/cm2-sec with an average of 5.6
aCi/cm2-sec
In spite of the fact that these measurements were made during the cold season with air tight
conditions we found only one building with radon >4 pCi/L suggesting that energy conservation
goals can be satisfied without compromising indoor air quality. We suspect that the geology and
the entry rate at which the radon infiltrates the building are the cause of high indoor radon levels
rather than the ventilation rate. At about the same time some residential buildings in Northeastern
Pennsylvania and Northwest New Jersey had high indoor radon levels that were suspected to be
associated with similar factors (with all the blame resting on the Reading Prong Geology that
included the Stanley Watras ‘Radon Hot” home.
To shed some light on the impact of home insulation and air tightening we made radon
measurements in residential buildings in Maryland and Pennsylvania. We measured radon in 41
homes in Maryland and in six all electric and in 31 randomly selected homes in Pennsylvania. The
31 homes were within a radius of 50 miles from Philadelphia Metropolitan area that included some
New Jersey homes. Both basements and living areas were tested on a three day-basis with the
EML charcoal collectors. The radon test devices were exposed in duplicate and were repeated
twice in each season.
The radium content of the surface soil was about 20% higher than those I measured in the New
York New Jersey study in 1975-78. When we used a trace gas to identify the source of radon, we
found it in the basement. The ventilation rates in these homes indicated low infiltration rates
suggesting that the electric homes were efficiently insulated and airtight. The house location, age
and air tightness due to efficient insulation are suspected for the higher radon concentrations the
number of homes is too small. When the Watras radon problem materialized and the Reading
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Prong geology became apparent tightening homes was not always to blame on the elevation of
indoor radon. The blame should rest on the radon entry rate rather than on the ventilation rate.
After the results of radon measurements in Pennsylvania were reported by Richard Oswald Terradex Corp. and by EML, the Philadelphia Inquirer Sunday Magazine of November 21, 1982
came up on the front cover with a scary headline and picture. On the cover in full color they
depicted a home as “Home Deadly Home” glowing by the intense radiation. The description of the
front page said; “Its like a horror movie come true. An odorless, colorless radioactive gas is
drifting into homes from underground, causing thousands of deaths a year”. What’s more, the
better insulated the house, the more lethal the dose.” The impact of this newspaper at a prime time
was felt throughout Pennsylvania. Professor Harvey Sachs from Princeton gave my name to the
magazine as one of the experts in the radon field. The next day Monday morning November 22, I
received 160 telephone calls requesting information on radon. For all this I have to thank Harvey.
Half of the homes in Pennsylvania were constructed with energy conservation in mind. About 40%
of the living rooms of homes in Pennsylvania excluding the six all electric homes had radon levels
above 3 pCi/L. About 50% of the living areas in Maryland homes had radon above 3 pCi/L. In all
the six all electric homes in Pennsylvania the radon exceeded 3 pCi/L the recommended limit (at
the time) for continuous exposure.
Roberta Baskin a target 7 Reporter from WJLA-TV in the Washington area requested EML’s
assistance to conduct a radon survey in Northern Virginia, Maryland and the District of Columbia.
EML, cooperated by supplying activated carbon collectors to test for radon in 46 residential
buildings. EML did the analysis and found half of the homes had radon three times greater than the
EPA accepted level. As a result, Virginia health officials have received so many calls from
concerned home owners that they set up a hot line to answer inquiries about radon. A few weeks
later the State of Virginia began a state-wide radon survey of 800 homes randomly selected
While we continued to make radon measurements in different parts of the US, we intensified
our research efforts in addressing the behavior of radon decay products (RDP) indoors. One factor
that has a great influence on the WL indoors is plate-out on surfaces. Plate-out causes problems in
both the design and the use of instruments that measure RDP that estimate the health risk. The
main purpose of our plate-out studies was to determine its magnitude under different conditions of
particle concentration, particle size and the rate of air exchange. Our investigation of plate-out was
conducted in two radon chambers: one was (1.9 m3) made of wood and in a large radon chamber
(20m3) the size of a small bedroom made of stainless steel. Test were conducted with particle
concentrations at 2,000 particles/cc and up to 170,000 particles /cc. The fraction of RDP that
deposited on 10 cm discs suspended inside the chambers or fixed on the walls of the chambers was
measured after the surface radioactivity reached equilibrium. The results in 13 experiments
showed the following. With low particle concentration at 2,000 particles/cc the airborne radon and
WL concentrations were 307 pCi/L and 0.31. The corresponding deposited WL was 1.88
representing 86% of the total radioactivity. The ventilation rate and the geometric particle
diameter were 0.02m3/min and 0.063 microns.
In another test where the particle concentration was 175,000 particles/cc and the radon and the WL
concentrations were 390 pCi/L and 2.2 the corresponding deposited WL was 0.1 representing only
4% of the total radioactivity. The corresponding ventilation rate and the geometric particle
45
diameter were 0.02 m3/min and 0.151 microns. The laboratory experiments showed that there is an
inverse relationship between the percentage of plate-out and the airborne particle concentration
and the WL ratio increases as the particle concentration increases. The results indicated that the
average attachment rate of RDP atoms and the mean attachment coefficient remain constant for the
particle sizes we studied.
In 1982, the Air Pollution Control Association was having its 75th Anniversary Annual
Meeting and Exhibition in New Orleans. I was invited to present a paper on the Characterization
of Radon levels in Indoor Air. My presentation was probably the first of its kind to be presented at
an APCA meeting. The purpose of my presentation was to describe the different types of
monitoring and sampling techniques that could determine the radiation burden of the general
public from radon and RDP. I described the sources of radon, sampling strategies, including grab
sampling, integrating and continuous measurements for both radon and RDP. I also described
special measurements such as particle size measurements of RDP and their fractional deposition in
the respiratory tract for radiation dose calculation. The meeting was one of the largest I ever
witnessed. In the banquet there must have been over 200 tables set up for dinner. My fond memory
from this meeting was the classical Monteleone Hotel and its Carousel Oyster Bar. You could have
had the freshest oysters in New Orleans in its friendly environment. I had oysters for breakfast and
dinner. At the New Orleans airport on my way back to NY, I indulged on another dozen oysters.
The US EPA was established in 1970 to oversee and regulate the quality of the environment.
Up to 1984, most of the research and measurements on radon was conducted by DOE. EPA began
to take over some of the remediation activities addressed by DOE to clean up sites contaminated
with uranium and radium tailings. In 1984, the home of Stanley Watras in Berks County,
Pennsylvania was found to have the highest indoor radon level ever recorded.
The radon problem in the US started to become an issue when Stanley Watras a construction
engineer at the Limerick nuclear power plant coming from his home set off the radiation alarm
when he entered the plant construction site. Upon investigation it was surmised that Mr Watras
became radioactive while in his residence. The State officials and radiation specialists from the
Philadelphia Electric Co identified that his home was dangerously radioactive due to high
concentration of radon and RDP.
At a concentration of radon at 2,700 pCi/L and 50% equilibrium the concentration of RDP was
about 13 WL. Mr Watras clothing and his body were saturated with deposited RDP with a
radioactive half-life of about 30 minutes. When he entered the nuclear plant site, enough Pb-214
and Bi-214 were still available to trip the gamma radiation alarm. Further investigation by State
and Federal officials learned that thousands of homes located on the geological belt called the
Reading Prong contain dangerous levels of radon. Fortunately for Mr. Watras, his home was
mitigated as a demonstration project at a cost of $32,000 borne by the Philadelphia Electric Co
which operated the Limerick plant. Six months after the Watras family moved out from the
radioactive home they were able to return into a safe environment. Stanley Watras however, made
statements that were contradictory of what we know about the ill effects of radon. He claimed that
when he first moved his family in his home with high radon his wife’s and his dog’s ailments
disappeared suggesting that radon cured them. When they moved out to have the home fixed their
ailments returned. What kind of message he was trying to pass to his neighbors with homes with
46
high radon levels? After he made these controversial statements, he accepted the offer of
Philadelphia Electric Co to have his home mitigated at no cost to him. This did not sit well with
Kay Jones who was looking for financial help to fix her home located across the street with a radon
level that was higher than the Watras residence. Kay Jones home had the highest radon level ever
recorded in a house in the United States. Ms Jones was frustrated with the authorities that were
reluctant to take care of her radon problem as they did for Mr.Watras. She was an outspoken critic
of the government response to the radon issue that forced her to form a citizen’s group of
Pennsylvanians Against Radon to lobby for federal and state funding for residents whose homes
had high concentrations of radon. When she went to Washington to lobby for federal assistance, I
went at the same time to demonstrate some measurement techniques for assessing the health risk
from radon in the Halls of Congress. A small workshop was hosted by Representatives Claudine
Schneider of Rhode Island and the late James Scheuer of New York my local Congressman in NY
at that time. They arranged for a conference room in the Capital building to unveil their bill that
was intended to study indoor pollution. They introduced their bill at a news conference where I
demonstrated the evils of smoking measuring the particle concentration in air in the conference
room before and after smoking.
Using a portable Gardner condensation nucleus counter (particle counter) I measured about 7,000
particles/cc. After congressman Scheuer lit his long cigar the smoke particle concentration jumped
to over one million particles/cc. I explained the synergistic effect of smoking with radon
and the increase of the WL in the presence of high particle concentration. With EML scintillation
cells I measured the radon concentration in several places. In the large room where we had the
press conference the radon was 0.7 pCi/L. Congresswoman Schneider told me that her father died
from lung cancer after living for many years in Clairton Pennsylvania about one-half mile from the
house where I was born. Her concern was that her father was a machinist and had a workshop in
the basement of the house. When I measured the radon with EML charcoal canisters I found a level
above 4 Ci/L.
During the George Bush (the father) administration, I was asked to send some charcoal canisters to
measure radon in the White House. Unfortunately I never found what happened to the test devices.
They were not returned to EML and I never found out if they were exposed at all.
In another instance I was asked to make measurements in a classified underground area outside of
Washington. I was not sure of its exact location (it was classified). Since I had Q clearance I was
escorted to the underground military like base to investigate the concentration level of radon.
Inside there were facilities such as a hospital, a large cafeteria, sleeping quarters and a very large
military conference room reminiscent of the “War Room” for politicians and generals depicted in
the 1964 movie Dr. Strangelove –How I Learned to Love, Stop Worrying and Love the Bomb- in
which the British actor Peter Sellers played an insane general. The entire underground area was
well ventilated resulting in low radon and WL concentrations. The biggest concern was how much
radon was in the large war room. With the ventilation always ON, several radon samples
throughout the day measured <1 pCi/L. There were no occupants during my visit except for a
skeleton crew that maintained the underground quarters for any emergency that may arise.
After the discovery of high radon levels throughout the Reading Prong in Pennsylvania, I
was approached by News Watch 16 a television station in Northeastern Pennsylvania for EML’s
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cooperation in making radon measurements in the counties that can be reached by the WNEP TV
station. I was happy to supply them with our 4-inch charcoal canisters. It was a great opportunity
for me to collect more radon data in different regions of the US. Duplicate canisters were exposed
for 4 days in the living rooms and basements of 42 homes. The results showed that the percentage
of homes with radon >4 pCi/L homes was higher than other locations where I made measurements.
The action level was exceeded by 19% and 40% in the living rooms and basements respectively. I
was interviewed on their TV to discuss the measurement results I obtained in the 42 houses and I
recommended that the Pennsylvania authorities undertake a more extensive radon survey. As a
result of our measurements the Northeastern Pennsylvania the Environmental Council and Wilkes
College made arrangements to test an additional 2,000 homes in the 22 counties the TV signal
reaches. They purchased long-term alpha track detectors from Terradex Corp. for the larger
survey.
In late 1984, the American Society of Heating Refrigerating and Air Conditioning Engineers
invited me to present an overview paper on radon sources, radon and RDP concentration levels in
residential buildings. This was the first time the audience was introduced to the newly emerging
indoor air pollutant. The meeting was held in Honolulu Hawaii. Because I had an audience that
was unfamiliar with the radon issue, I had to talk about the physical characteristics of radon and
RDP and about the factors that affects them indoors. I covered in detail the different methods and
instruments available at that time.
I also familiarized the audience about other parameters that were needed to calculate the radiation
dose to the lungs. Finally I presented indoor radon and RDP measurements made directly by EML
or in cooperation with other agencies over a period of 10 years (1974-1984). The data were
collected in 470 buildings in 13 different geographical areas.
The geometric mean WL in the living areas ranged from 0.0023 – 0.0173. The high mean WLs
were 0.0152, 0.0165 and 0.0173 in Damascus MD, Eastern PA and Butte MT respectively. I
concluded my talk with the following statement. The measurements for radon and RDP in the US
so far suggest that there are anomalous regions where the soil radon entry rate
is well above average.
Because of the considerable interest in indoor radon after the high radon levels found in the
Watras’ home, the Air Pollution Control Association sponsored a Specialty conference in
February 1986 to shed some light on the subject. The purpose of the conference was to review past
experiences and characterize the current state of knowledge on radon measurement and control of
indoor radon in the US, Canada and other countries. The conference was held in Philadelphia a
central location near the birthplace of the radon program. The proceedings included a) Nature of
the problem. b) Measurement methods field studies and results. c) Exposure and health risk. d)
Methods of control and costs. e) International perspectives on environmental standards and
guidelines. Being the person who conducted hundreds of radon measurements in uranium mines
and in residential buildings I was invited to give an overview of the radon problem and to talk
about instruments and methods for measuring indoor radon and radon progeny concentrations. In
my presentation I covered the different types of radon testing such as grab sampling, integrating
and continuous and explained their usefulness in addressing short-term testing that seemed to
become very popular.
48
For research purposes such as real-time changes in radon and RDP concentrations radon transport,
behavior and interaction with the indoor environment more complex continuous or
semi-continuous monitoring instruments were recommended. I also emphasized that the ability to
obtain accurate measurements at low concentrations and the qualifications of the user determines
the quality of measurements These two criteria combined with proper instrument calibration are
the essential elements in a successful radon monitoring program. Later, these recommendations
convinced EPA that a Radon Measurement Proficiency Program was needed to evaluate all radon
test devices in a quality assessment program.
On Monday February 24, 1986, before the regular Specialty Conference I conducted my first
8-hour radon course. I believe, it was the first course ever for people who were getting into the
radon measurement and control. If memory serves me correct there were about 35 participants. I
assumed the students knew very little about radon and I had to present an overview of the indoor
radon problem. Some of students in that class later had become very successful mitigators. The
Conference was attended by about 325 people representing government, industry, academia and
the international community. A book containing 55 research, policy and practice papers were
included to provide the reader with up-to-date and authoritative information on a variety of facets
of indoor air quality.
After the establishment of the International Intercalibration and Intercomparison Program
by the Nuclear Energy Agency (NEA) of the Organization for Economic Cooperation and
Development (OECD) in cooperation with Commission of European Communities (CEC), EML
was selected and designated as the reference laboratory to serve as the calibration center for
non-occupational exposure measurements in North America.
Inter-comparisons of RDP measurement methods and equipment began in 1987 after the
high radon levels found in Pennsylvania and the establishment of a new industry to address the
radon problem. We always had better agreement between the different radon methods than
between RDP methods. The detection of RDP presents special problems due to their properties
such as the attached or unattached state and on their size distribution. Many of the instruments that
measured RDP were poorly designed resulting in substantial loss (plate out) of RDP before they
reached the filter underestimating the WL.
As the radon problem in the US was becoming known with the help of EPA and by the
media. EML was getting involved in radon surveys in different regions. With the cooperation of
local health officials, EML undertook a radon survey in 380 buildings in six States. The activated
carbon collectors developed at EML were used to measure radon in basements, living rooms of
each residential building and in some work locations of several plant buildings during summer and
winter. The activated carbon collectors worked very well throughout the study period. The lowest
concentrations were found in Long Island NY as expected and in South Carolina. The remainder of
the test areas showed a substantial number of buildings to have radon above EPA guideline action
level. The arithmetic mean concentration of radon in the living areas in the different regions
ranged from 1.1 pCi/L to 9.3 pCi/L during the winter months. The dose equivalent to the lungs of
the occupants of these buildings ranged from 1.4 – 10.7 rem/y. Based on these risk estimates it
seems that a substantial fraction of the Northeastern U.S. population is exposed to radon levels
high enough to warrant immediate attention. The results were presented at the American Chemical
49
society Symposium in New York. The Symposium proceedings were published in February 1987.
The data from the seven Eastern States and from other EML radon surveys were used by Tony
Nero to study the distribution of airborne radon concentrations in US homes. Tony’s paper
published in Science 234, 992-997, 1986 it has become a classic. I highly recommend it. It is very
enlightening and informative.
During the meeting, arrangements were made for a special panel to discuss the radon issue in the
US. The panel consisted by Bernard Cohen, Naomi Harley, an EPA representative and myself.
What made an everlasting impression on me was B. Cohen’s advice and recommendation; “ we
should not worry about radiation exposure from nuclear power plants and concentrate our
resources on radon studies” suggesting that radon was far the worst cause of indoor radiation
exposure. This was before he expounded the threshold theory.
After the high radon levels were found in Pennsylvania, there was a lot of anxiety among
building residents. Newspaper articles and editorials, radio and television were highlighting radon
as the number one indoor air pollutant with serious health consequences. EPA finally, as a
regulatory government agency stepped up to the plate and set the wheels in motion to address the
radon problem facing the nation. One of the first things addressed by EPA was the status of the
radon measurement technology and how much measurement accuracy was required to measure
environmental radon levels.
As EPA did not have a radon calibration facility they asked me if I could help them to conduct their
first radon measurement proficiency program in the EML radon facility that I set up in 1964. Well
I could not say no to another government agency that was getting ready to alleviate some of my
radon survey work and allow me to do more research. In January 1986, 17 participants submitted
their instruments for performance evaluation in the EML radon facility. In the 2nd radon
proficiency exercise in July EPA submitted instruments from 70 participants. In November 1986
in the 3rd radon proficiency exercise there were 170 participants. The logistics of the three
proficiency exercises were handled by EPA contractors placing and retrieving the test devices in
the EML facility in New York.
Beginning in 1987, EPA conducted the radon proficiency program in its newly constructed radon
chambers in Montgomery Alabama and later in Las Vegas. At the end of May 1986, EPA released
the list of 19 companies as proficient in measuring radon. After the second exercise in the EML
radon facility, EPA listed 75 companies as qualified to make short-term radon measurements.
Forty-five of these companies were providing nationwide radon testing. The remainder, were
operating within States. Most of the testing companies were commercial firms or laboratories
EPA convened a group of experts in Washington to discuss what kind of accuracy is deemed
appropriate for an instrument to be acceptable. John Harley (EML director retiree) suggested 50%.
Ron Colle from the Bureau of Standards was pushing for 10%. After some discussion, I felt that
25% was probably the best we could have come with. I already had experience with most of the
available radon instrumentation and I was convinced that an error of 25% was acceptable. Radon
unlike many pollutants can be measured easily and very accurately with the present
instrumentation. Now you know how that ± 25% was established. As I mentioned earlier, the
Equilibrium Ratio (ER) of 50% assumed by EPA was taken from data in the classic study I
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conducted in 21 houses in the NY-NJ Metropolitan area back in 1975-77.
For all the help I rendered to EPA, I received a tribute of appreciation plaque from the agency that
says “Tribute of Appreciation Presented to Andreas C. George for his generous donation of time
and technical expertise in coordinating radon chamber operations during the Radon Measurement
Proficiency Program’s first year of operation”.
With the main radiation concern from airborne radon and RDP, the gamma exposure from
RDP was not addressed by anyone until EML began to look into it by conducting experiments in
the 2.8 x 2.8 x 2.4 meter radon chamber. With the invaluable help and instrumentation provided by
Kevin Miller from the Radiation Physics Section of EML, we calculated an exposure rate in the
center of the chamber to be 1.8 micro R/h per 100 pCi/L. At a height of 60 cm above the floor
where we positioned the EML ionization chamber the gamma rate was 1.6 micro R/h. All RDP
were attached due to high particle concentration and we assumed minimal plate out of RDP. Under
high plate out conditions where Pb-214 and Bi-214 deposit on the chamber walls, floor and ceiling
the exposure rate in the middle of the chamber fell by about a factor of two.
In an experiment in the EML chamber with 100,000 wax particles/cc and with the radon
concentration at 100 pCi/L the gamma dose rate was about 13 nGy/h per 100 pCi/L at a height of
60 cm. In the case where there is significant plate out of RDP, the gamma dose to the occupant of
the home will increase because plate out occurs on the body and clothing. Just recall Watras’s high
gamma radiation from his body and clothing. From all the experiments we conducted in the
20 m3 radon chamber we concluded that the effective dose equivalent from the inhalation pathway
is about three orders of magnitude greater than that from the external gamma radiation for a given
concentration of radon in indoor air. These experiments were conducted in 1986 and a paper as a
Note by Kevin Miller and myself was published in the Health Physics Journal Vol. 54 No: 2,
(1988).
In January 13, 1987, I was one of the DOE employees selected to be honored in Washington
by the Secretary of Energy John S. Herrington. The DOE Secretary on that day said: Today, we
recognize a select group of employees, the men and women whose dedication, initiative and hard
work is being honored at this Fourth Annual Department Awards Ceremony. We have every
reason to be proud of their distinguished work, of their unique and innovative contributions to our
energy policy and of the great credit they have brought to the Department, to the United States
Government and to the President.
I was presented with the “Meritorious Service Award” the second highest award granted for
achievements which substantially contributes to the accomplishment of the mission or major
programs of the Department of Energy. Also, I was presented with a Plaque I mounted on the wall
of my study room. I was selected specifically for the Distinguished Service Medal at ceremonies in
Washington for my work in expanding man’s knowledge of Radon.
I was selected for the award in recognition of my scientific efforts and achievements extending
over two decades in studies devoted to assessing human exposure to low level radiation
particularly in the field of indoor radon. The Environmental Measurements Laboratory (EML)
DOE, submitted the following information about my years of work on Radon for the Meritorious
Service Award.
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In the 1960’s after more than 50 field trips to underground uranium mines in Canada and
the U.S. George had gathered the data necessary to understand the health effects of radon.
In the 1970’s, George focused his research on radiation exposure to people living in homes
built with waste materials from uranium mining. Still later, George began to look at
ordinary houses, and the effects that increased energy conservation measures could have
on radon build-up. As a tangent of his research, George explored practical, reliable yet
inexpensive systems to measure environmental levels of radon. As a result he developed
the activated carbon method to collect environmental radon during a 2-7 day exposure. The
charcoal method became the most popular and inexpensive technique representing close to
70% of the short-term radon measurements in the U.S.
The director of EML the late H. Volchok said of George “His energy, creativity and
resourcefulness have inspired his colleagues worldwide. His leadership in radon research circles is
so widely known that in a scientific article in a Westchester NY newspaper he was cited as Andy
George, “the Radon Guru”.
In July 1987, I received the science award and a plaque from the American Hellenic
Educational Progressive Association (AHEPA) at the annual convention held in New Orleans.
It was a great honor and a privilege for me because I knew many AHEPANs among the 2,000
members attending the banquet to celebrate the success of another annual convention. In a
previous annual AHEPA convention in Washington D.C. I met and talked to Bob Hope who was
the Master of ceremonies during the banquet.
The first intercomparison of Radon Decay products (RDP) was conducted in 1987 at EML.
The purpose of the intercomparison was to evaluate the state-of-the methods and equipment used
in North America for the assessment of human exposure to RDP. The exercise included 12
participants from Canada and the Eastern United States. Grab samples were collected for RDP at
low and high concentration of particles and RDP. Very good agreement was observed among the
participants ant the reference lab (EML). Also good agreement was observed with automated
instruments when tested at a highly RDP attached environment. In one automated instrument, the
WL was underestimated by more than 25% in a low particle concentration and low radon
environment. In later intercomparisons several automated instruments showed the same effect due
to plate out of RDP before they reached the collection filter.
The effect of plate out can be reduced by designing a better filter detector assembly. Grab sampling
methods with an open face filter precise air flowrate and accurate alpha check source certified by a
single reference lab resulted in the most accurate RDP measurements.
The findings of the RDP Intercomparison were reported at the Fourth International Symposium on
the Natural Radiation Environment held in Lisbon December 7-11, 1987. More than 200 scientists
from 25 countries and six continents participated .Of the total 120 papers at the Symposium, 65%
were on radon and RDP covering radon behavior, metrology, surveys, risk assessment and
mitigation techniques. DOE co-sponsored the symposium. I presented a paper on indoor radon
progeny particle size distribution measurements made with two different methods. Earl Knutson
and Keng Tu presented a second paper on the intercomparison of three diffusion batteries for
measuring the size distribution of RDP. Isabel Fisenne of the radiochemistry division at EML
presented a paper on Uranium in Humans. Wayne Lowder another EML employee and one of the
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key organizers of the Symposia were present during the 11 days of the meeting. It rained mostly
throughout the meeting. During the dinner reception we were treated to an extravagant meal in a
beautiful underground restaurant. During the weekend I managed to accompany Chick Craig
(from EPA), his wife and Keng Tu for a visit to the shrine of the “Lady of Fatima”. It was quite a
sight to behold watching pilgrims trying to approach the site on their knees from a starting point
about 1,000-2,000 feet from the shrine.
In September 1988, the Public Health Service and EPA issued a National Health Advisory
warning that radon induced lung cancer is one of the most serious public health issues and urged
that all homes be tested for radon. At EML, we had extensive experience with radon measurements
with the charcoal canister method for 2-4 day exposures. We made radon measurements in
hundreds of homes with successful results. However, we wanted to extend the measurement time
of the open face charcoal canister from 2-4 days up 7 days of exposure. We experimented with
different diffusion barrier materials and different charcoal material to apply in the modified
charcoal canister that was developed in the late 1970’s. The original open face canisters performed
very well in environments with humidity up to 70% and where the radon varied by a factor of 5
during the 2-4 day exposure.
The modified canister was designed to operate at humidity ranging from 25%-90% and in an
environment where the radon varied by more than a factor of 10. Variation of radon by a factor of
10 can occur in anomalous situations. In most of the measurements made with continuous radon
monitors the variation was usually by a factor of 2-3.
The diffusion barrier canister was designed to integrate accurately under the most extreme
conditions of radon concentration and humidity. The calibration results for the modified canisters
show that radon is adsorbed linearly for all conditions of humidity up to 7 days of exposure. The
diffusion barrier maintains the amount of adsorbed water below the break-point of the carbon. It
should be noted that the calibration curves obtained with the modified method apply only to the
radon collectors and the analytical system used at EML. In other words any other lab that goes the
charcoal collection method for radon should investigate the characteristics of the charcoal they
will use and calibrate them with their unique analytical system. You cannot copy another lab’s
calibration curves. The development and calibration of the modified EML charcoal collector for
radon was published in the Health Physics J. Vol. 58, No. 5, May 1990, titled “An improved
passive activated carbon collector for measuring environmental Radon-222 in indoor air. Authors;
A.C. George and T. Weber.
The EML charcoal canister modified with a diffusion barrier became popular very quickly. EPA,
PA/DER and RTCA adapted the diffusion barrier concept and developed and calibrated their
diffusion barrier equipped charcoal canister obtaining similar results. They demonstrated that they
could measure the average radon concentration very accurately at high humidity and under
extreme variation of radon concentration. The EPA diffusion barrier canister containing 70 g of
activated carbon equipped with a teflon disc as the diffusion barrier was described at the 1992
International Symposium on Radon and Radon Reduction Technology in Minneapolis, MN. I
believe they never published the paper in the proceedings.
However, EPA published a shortened version of the diffusion barrier canister as EPA report
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520/5-90-032 November 1990, titled U.S. EPA NAREL Standard operating procedures for
Radon-222 measurement using diffusion barrier charcoal canisters. I had access to the original
EPA paper with the detailed evaluation of the diffusion barrier canister. I discussed the EPA paper
findings in a paper I presented at one of the AARST annual meetings. In my presentation I
inter-compared the Sensitivity and Accuracy of Radon Measuring Instruments and Methods.
Radon measurements conducted in the field and radon chambers by EML, EPA, PA/DER and
RTCA using diffusion barrier canisters showed average radon values to be in very good agreement
with the average radon value obtained with continuous radon monitors when exposed up to 7 days
under extreme conditions of humidity and variation of radon concentration. Also diffusion barrier
canisters like the open face canisters are the most sensitive method for measuring radon. For
example the sensitivity of CRMs ranges between 0.17 - 2.8 net cpm/4 pCi/L whereas the
sensitivity of the diffusion barrier canisters ranges from 48 - 145 net cpm/4 pCi/L. The sensitivity
of a 4-inch open face charcoal canister is >200 cpm/4 pCi/L.
In the mid 1980’s while we were refining the EML methods for measuring the particle sizes
of radon decay products we conducted size distributions measurements in a variety of
indoor environments in urban, suburban and rural areas. Measurements were conducted in six
occupied houses located in five different areas in Morristown, Edison, Princeton, Clinton and
Belle Mead all in New Jersey. Belle Meade was rural with essentially no traffic. However, in this
house were three smokers and none in the other 5 cities. All homes used gas stoves for cooking
purposes. Particle size measurements were taken during cooking, cigarette smoking and during the
use of kerosene and electrical space heaters in the homes.
The results show that kerosene or electrical space heaters and gas combustion in stoves produce
small particles while cigarette smoke and frying meat produced relatively large particles with a
range of 0.108 – 0.203 microns. These particles were a factor of 2-3 larger than those produced by
the kerosene and electrical space heaters and gas stoves that ranged from 0.044 – 0.095 microns. In
the rural areas unlike our previous measurements in the absence of space heaters, the particle sizes
were larger with diameters ranging from of 0.221 – 0.274 microns. Radon decay products attached
to cigarette smoke and food frying particles have diameters that are consistent with the value of
0.150 microns adopted by the ICRP in 1987. Most of the minor particle mode (unattached fraction)
were <0.005 microns or 5 nanometers. Our findings were published in the Aerosol Science and
Technology Journal Vol. 15; 170-178 (1991). Authors were E. Knutson, Keng Wu Tu, and A. C.
George
In 1989, I was invited to present an overview paper on Instrumentation for Measuring
Environmental Radon and Radon Decay products at the Meeting of the IEEE Transactions
on Nuclear Science in San Francisco California. In the past, the IEEE meetings described all
types of electronic instrumentation but none dealt with Radon or RDP instruments and methods. I
accepted the invitation and prepared my talk to be given at a special session on radon. The meeting
was scheduled to take place in a large hotel in the San Francisco Bay area. I was looking forward to
visit San Francisco one of my favorite cities. Unfortunately an earthquake with the magnitude of
6.9 on the Richter scale occurred on October 17, 1989 just a few days before the meeting was to
take place. The Hotel for the meeting was located in San Francisco Bay area that was hit very hard
by the earthquake that lasted almost 15 seconds. The hotel suffered substantial damage due to
liquefaction of soil that was used to create waterfront land. The earthquake hit while the 3rd Game
54
of the 1989 World Series baseball championship was just beginning nearby.
The meeting was rescheduled in a large hotel in San Francisco where I presented my paper.
Because the audience was mostly electrical engineers and instrument manufacturers, I focused on
instruments that are necessary to measure radon and RDP. I discussed the types of radiation used
with a particular instrument and explained its principle of detection. Also, I discussed what is the
appropriate duration for a test to obtain a useful result. Radon and RDP instruments are specialized
devices designed to address the needs of the radon measurement industry that suddenly began to
emerge all over the U.S. I described other criteria used in the design of these specialized
instruments such as field measurement applicability, portability, convenience, reliability and cost.
I tried to make the audience aware that with the recent increased demand for indoor radon and
RDP measurements, instrument development is focusing on the design of inexpensive devices for
short-term testing used in screening studies, as well as on more complex and expensive
instruments that can be used both for short-term and long-term measurements used in research and
investigation programs. My recommendation to the audience was; that the ability to obtain
accurate measurements at low concentrations depends on the qualifications of the operator who
uses properly calibrated instruments for a specific application.
The instruments are usually made of individual component parts performing different functions in
a whole system and the entire system must be calibrated under conditions that approximate those
in actual field situations. The paper authored by yours truly was published in the IEEE
Transactions of Nuclear Science Vol. 37, No. 2, April, 1990.
In March 1989, we were asked to investigate the feasibility of using Radon, Radon Decay
products (RDP) and Thoron Decay Products (TDP) as atmospheric tracers to help
determine local air mass flow patterns. Mauna Loa on the big island of Hawaii was chosen as
the place to conduct our study. The Mauna Loa observatory is a premier atmospheric research
center where monitoring data are collected related to atmospheric changes. The remote location
with undisturbed air and minimal influence of vegetation and human activity was ideal for our
study. The temperature at night is around 35 oF. At sea level at Hilo ranges from 78-83 oF. The
local air flow is up-slope during the day and down-slope during the night.
Two teams consisting of Adam Hutter, Frederick Wilson, Mark Maiello and A. C. George,
traveled to the big island of Hawaii to conduct radon, RDP and TDP measurements during the
daytime and nighttime. We stayed in Hilo (sea level) and traveled by car about 45 miles to climb
slowly to the Mauna Loa observatory at an elevation of 11,100 feet. The daily drive from Hilo to
the observatory took about 2 hours. There was no vegetation or trees, birds or evidence of water
anywhere along the last 10 miles. At night it was very difficult to navigate the zig-zag roadway cut
out of the lava bed. The General Services Administration (GSA) provided us with a vehicle that
could negotiate driving the last 10 miles on the twisted road cut through a desert of lava. We
carried lots of sampling and counting equipment. Frederick Wilson an electrical engineer as a
member of one of the teams came along to make sure our instruments were functioning properly in
the harsh environment at an altitude of 11,100 ft. On our first day we set up and tested our
equipment and everything was found to be in good working order.
55
By the end of the first day Fred Wilson received a telephone call from his wife informing him of
the death of his mother in-law. Fred had to fly back to New Jersey and be with his family. This
unexpected event left three EML radon rangers to conduct measurements for 10 days. For
measurements at night it was necessary to have two investigators working as a team in this isolated
place. Mark Maiello and I took the night shift while Adam Hutter had to work alone during the
daytime. Working at night was difficult for both of us.
We usually had an early dinner in Hilo. By the time we made it to the observatory we experienced
a severe case of hiccups that lasted for several hours. Mark Maiello was the driver for the night
shift. I was the co-pilot. When we encountered dense fog on the road I had to walk in front of the
car to guide Mark to stay on the road. On one occasion while driving back to Hilo at down, Mark
stopped the car because he was feeling strange and uncomfortable due to the changing altitude.
Now I know why astronauts have to undergo so many years of training to condition themselves to
survive and function in different environments. I was affected to some degree with the change in
altitude but I was able to take over and drive on the paved road back to our hotel in Hilo. We had
breakfast and tried to sleep during the day and then drive back to Mauna Loa in the early evening.
Adam Hutter, the youngest of the three radon rangers was very well acquainted and proficient with
all aspects of the measurements we were planning to conduct. His heroic individual effort
contributed enormously to the success of our study. Radon concentrations were expected to be low
at 11,100 ft elevation and all grounds covered with hundreds of layers of solid cooled and hard
lava. We collected radon by passing air at 1 m3/min. for 1 hour through a specially designed
activated charcoal canister that was chilled in dry ice during sampling.
The charcoal canister was sent back to EML in New York to be analyzed by Isabel Fisenne the
master operator of the HASL pulse ionization chambers. The concentration of radon and thoron
decay products were measured by sampling on 4-inch filters at a very high air flow rate. The filters
were alpha counted for 11 hours and the individual decay products were calculated using the
Raabe, Wrenn least squares technique. In all, we collected 37 outside air samples adjacent to the
observatory. Most of the radon measurements were < 0.03 pCi/L. In general the radon and thoron
decay products were low when free tropospheric air was present (downslope and trade wind
conditions), and consistently higher when surface air from the island broke through the trade wind
inversion layer (upslope conditions). The data suggested that RDP and TDP monitoring can
provide new and useful information to help identify the different air flow patterns present at
Mauna Loa. A paper coauthored by the four radon rangers and Isabel Fisenne, Richard Larsen and
Harold Beck was published as USDOE Report EML -352, 1990.
On Sunday, our only day off, we visited the area that was completely covered with cooled lava that
streamed through a couple of years earlier. We were allowed to walk on it until we reached a point
about 500 feet where the steam was rising when the hot lava hit the sea. At night a reddish glow
was visible when the hot lava was flowing in the underground channel that damped its contents
into the sea creating a very large cloud of steam.
When a special meeting on indoor radon and lung cancer was held in Richland Washington
Earl Knutson and myself were asked to present the reanalysis of the size distributions of radon
decay products obtained in 1971 in four uranium mines in New Mexico. The original data
published in two separate journals were based on the assumption that the RDP consist of distinct
56
unattached and attached species that can be sampled and analyzed separately. In the reanalysis of
the original data the RDP were treated as a continuous spectrum of particle sizes ranging from 1 to
1,000 nanometers (0.001 – 1.0 microns), covering both the attached and unattached RDP. In the
reanalysis, 9 out of 26 samples were unimodal agreeing closely with original analysis done in
1971. Eleven of the reanalysis data had a bimodal structure with widely separated modes evoking
the classical idea of attached and unattached RDP. The Dose conversion Factors (DCF), from the
reanalysis of the 1971 data, ranged from 5.7-28 mGy/WLM with an average of 14mGy/WLM. The
new average DCF value is about three times higher than the 5 mGy/WLM given in the NCRP
report 78 as typical for mining environments. The reanalysis report authored by E. Knutson and A.
C. George was published in the proceedings of the 29th Hanford Life Sciences Symposium: Indoor
Radon and Lung Cancer: Reality or Myth Richland Washington October 16-19, 1990.
The recycling of charcoal canisters used in indoor radon measurements was examined by
yours truly in cooperation with Professor Philip Kearney of the department of physics Colorado
State University. The purpose of the study was to determine that the recycling process can be
continued without significantly affecting the response of the canister. Charcoal canisters
manufactured by Colorado State University were exposed in relatively uncontrolled situations
such as what might be encountered indoors from April 1988 through June 1989. Exposures varied
from 3 to 8 days.
After counting in Fort Collins Colorado, the canisters were regenerated by heating for 8 to 12
hours at about 100o C. At different intervals, throughout the study, the canisters were sent to EML
for exposures in the 20 M3 radon chamber. The canisters were then returned to Fort Collins for
analysis. The results from 51cycles of exposure indicate that there is no degradation of the
collection efficiency of the canisters. It appears that these canisters could be reused for
significantly larger number of cycles. {Similar results were demonstrated with the RTCA
diffusion barrier canisters that have been in use since 1988}. Recycling charcoal canisters provides
an economic advantage for radon firms that use them for short-term radon measurements. The
paper was published in the Health Physics Journal Vol.40, No.5 (1991). The authors were, P.
Kearney R. V.Huff and A. C. George.
On veteran’s day November 11, 1990, I became a grandfather. My daughter Diana gave birth to
little Andrew at Lenox Hill Hospital in Manhattan. I am writing about this happy event on
November 11, 2012 on his 22nd birthday. Today he is over 6 feet tall and a senior at Mitchell
College in New London Connecticut. Little Andrew turned out to become big Andrew.
In 1990, I was invited to present a paper at the 5th International Symposium on the Natural
Radiation Environment to be held in Salzburg Austria the birthplace of Amadeus Mozart. The
Symposium was organized by the Commission of the European Communities, the US Department
of Energy, IAEA and the University of Salzburg. The symposium was not only on radon; many
other topics such as the radiological impact of non-nuclear industrial releases and the exposure of
the public and of workers to natural sources of radiation in non-domestic environments were also
addressed. Of the 163 presentations, 114 were related to radon with some on thoron. John Harley
the director of EML DOE, gave a brief history of radon measurements. He stated that there has
been more measurements of radon and RDP than of any other radioactivity and the measurements
are quite easy and someone is willing to pay for them. I presented my work on the deposition of
57
RDP in the nasal and tracheobronchial regions.
When radon surveys were undertaken by EPA and other radon professionals afforded me some
time to devote on research dealing with the better assessment of the radiation dose from radon and
RDP to the respiratory tract. To address this issue, I designed and tested a three-part device that
simulates the collection characteristics of the human nose and tracheo-bronchial region. The three
sampling devices were designed to operate simultaneously. One device collects the total
concentration of RDP; the second device consists of a 100-mesh wire screen that simulates the
collection characteristics of the human nose plus a back-up filter to collect the RDP that pass
through the screen. The third device has a single 100-mesh wire screen and four additional
400-mesh wire screens which together simulate the combined collection characteristics of the
nasal and tracheo-bronchial region. The back-up filter collects the activity that penetrates the
screen wires. The sampling system was evaluated in the EML radon chamber and in residential
buildings under known RDP and particle concentrations. The new sampling system ran
simultaneously with the EML standard diffusion batteries that determined the size of the
unattached and attached RDP. In environments with zero particles/cm3 (clean air with essentially
100% unattached RDP) the sampling device with a single 100-mesh wire screen measured 80%
nasal deposition.
In ordinary room air where the activity median diameter (AMD) of the RDP ranged from
0.100 – 0.305 microns the nasal and the tracheo-bronchial depositions averaged 5.3% and 4.7%
respectively. In the presence of cigarette smoke or wax aerosol both the nasal and
tracheo-bronchial depositions were lower averaging 1.6% and 4.0% respectively. Tests with
electric heaters and a methane gas flame resulted in very small particles with average nasal and
tracheobronchial depositions of 11% and 7.3% respectively. Such intense use of these devices
would rarely be encountered in residential buildings. We found very good agreement between the
new sampling system and the more complicated measurements made with conventional diffusion
batteries. The paper authored by A. C. George and E. Knutson was published in the proceedings of
the 5th NRE Symposium in the journal of Radiation Protection Dosimetry Vol. 45, No.1-4 (1992).
A second paper presented at the 5th NRE symposium in Salzburg authored by K.W. Tu, A..C.
George, W. Lowder and C. Gogolak was on Indoor Thoron and Radon Decay Products
measurements. Many research studies conducted by many scientific groups including EML
provided better understanding of indoor radon and RDP in terms of their physical properties their
transport and potential biological health risk with limited information on thoron and thoron decay
products (TDP). EML was asked to address this issue by conducting simultaneous RDP and TDP
in 40 houses in NJ. NY, Ill and Colorado. The instruments used for the study were calibrated in the
EML radon and thoron calibration facility with known and controlled conditions of RDP and TDP.
The field measurements were conducted in the ground floors and basements mostly in the winter
with some in the spring. The contribution of the thoron decay product WL was 3% when the radon
decay product WL level was >0.13 and 21% when the RDP WL ranged between 0.03-0.13 and
19% when the RDP WL was <0.033. The findings in this study demonstrate that the contribution
of thorn to the total WL is insignificant when the RDP WL is >0.1.The measurements in 23 single
family houses indicate that building materials rather than the soil are the main source of thoron.
The paper was published in the proceedings of the 5th NRE symposium in the journal of Radiation
58
Protection Dosimetry Vol. 45 No. 1-4 (1992).
At the conclusion of the symposium in Salsburg, several groups from the international community
participated in a radon intercomparison exercise inside a Spa in Bad Gastein Austria. Visitors to
the Spa, ride on small electric trains about 500 meters from the entrance for their therapy
treatment. They sit on benches for a few hours breathing the high concentrations of radon and RDP
and negative ions. The visitors believe that the abundance of negative ions invigorates them. Water
from the Spa is piped to the nearby tourist hotels for the guests to bath in them.
Earl Knutson and I, oversaw the measurement results of the different groups and intercompared
them in a short report. After the Bad Gastein intercomparison exercise, E. Knutson and I, we drove
to a Northern Bavarian city to intercompare methods for measuring the unattached RDP and
compare dose conversion factors calculated from the results obtained by three participating
laboratories. The participants were Steve Solomon from the Australian Radiation Laboratory, the
late A. Reineking from the famous university of Gottingen and E. Knutson and A. C. George from
EML, DOE.
The intercomparison was conducted in a house with elevated radon in October 1991. The results
showed that the unattached fraction had a median diameter of 0.009 microns. The median diameter
of the attached RDP ranged from 0.200 – 0.350 microns. The conversion factors measured by the
three labs differed less than 30%.
One evening during the field exercise we were invited to a birthday party for a young lady given by
the lady that owned the home we were conducting our study. There must have been 30 happy party
goers. The food was great. I never saw such a rich assortment of fish platters at any party
considering this small town was located inland in Northern Bavaria. We were treated graciously.
Personally, I enjoyed the abundance of good German beer and the fancy fish fare.
The paper authored by A. Reineking, E. Knutson, A. C. George, S. Solomon and Justin
Postendorfer was published in the journal of Radiation Protection Dosimetry Vol. 56, No. 1-4
(1994).
Thoron gas measurements are more difficult to make due to its 55 second short half-life.
Most of the gas decays in the soil and building materials. In the 1970’s we used the 0.5 liter two
filter tube successfully to measure thoron in mines and in the radon/thoron calibration facility at
EML. For thoron measurements in residential buildings I fabricated a larger volume (4.5 liter)
two-filter tube to improve thoron sensitivity down to 0.03 – 0.05 pCi/L. at a sampling rate of 25-50
L/min. The two filter method was evaluated at EML and later at the First International
Intercomparison and Intercalibration Workshop for thoron and its decay products at Elliot Lake
Canada in 1992. Also, in a secondary intercomparison exercise we found good agreement between
the two - filter method and the Swedish method that uses a scintillation cell and delayed
coincidence counting. Field tests in NY, NJ and PA were 5 hour long during the day and about 17
hours at night. The second filter or exit filter was counted for 3 to 16 hours. The average indoor and
outdoor radon and thoron measurements are listed in the Table below.
59
Indoor and Outdoor Radon and Thoron Measurements
Radon (pCi/L)
Thoron (pCi/L)
Bayside, NY *
1.20
0.10
0.05
0.10
6.30
2.21
0.98
0.16
0.16
0.32
0.14
0.97
25.40
0.43
22.20
0.43
32.40
38.80
0.62
10.40
33.40
58.00
0.38
7.00
Basement
Outdoors
Morristown, NJ
Basement
First floor
Outdoors – driveway
Outdoors – bare soil
Bethlehem, PA
Basement
Media, PA
Basement
West Chester, PA
Basement
Basement – sump dry
Riegelsville, PA
Basement
Basement – sump wet
*The house in Bayside NY is my residence in which all kinds of radon measurements and
experiments were conducted from 1964-1996.
The results show that indoor thoron levels at the breathing level are very low and thoron
measurements are difficult to make in homes with high radon concentrations. A paper authored by
E.O. Knutson, A. C. George, P. Shebell and C. Gogolak was published in the Journal of Radiation
Protection Dosimetry Vol. 56, No.1-4 (1994).
In the early 1990’s there were questions about the size of the fresh unattached RDP. To
address this question we conducted measurements to determine the size distribution of unattached
RDP in filtered room air. Using a serial array of wire screens in a 2-3 minute old air we measured
a mean diffusion coefficient of 0.048 cm2/sec. The results indicated that about 15% of the inhaled
unattached RDP penetrated beyond the nose into the tracheo-bronchial region. The paper authored
by A. C. George and E.O. Knutson was published in journal of Radiation Protection Dosimetry
Vol. 56, (1994).
After the radon problem was recognized by EPA, there has been an increased interest in
measuring radon RDP. Between 1986 and 1990 about 10 million homes have been screened for
radon of which about 10% needed to be mitigated. Because of the simplicity, convenience and cost
effectiveness in making radon measurements there has been a great move to conduct instrument
research and development to meet the demand of the newly developing radon industry. I realized
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early on that there was also a need for information on different instruments and methods in a
unified document for everybody involved in radon issues to be able to find the information and
help him/her to decide which best fits their needs. The selection of the instruments that I included
in my report is primarily based on my experience and that of hundreds of users in the commercial
sector. In the 1980’s I worked with every available device either through evaluation or calibration
in the EML radon facility. In 1986 when I conducted the first three instrument proficiency
exercises for EPA in the EML radon facility I became very familiar with every device or method
available at the time. My emphasis in this report was to be on portable instruments used for
short-term measurements to characterize indoor and outdoor radon environments. To do a
complete job on instruments, I had to place them in different categories, discuss their principle of
detection, the type of radiation detected and their sensitivity. In 1994 when I wrote the paper that
was published in the Health Physics Journal in 1995, I discussed instruments that were evaluated
and became available or known to me at some time before they were used in the field.
For radon measurements with continuous radon monitors I included pulse ionization chambers
manufactured by EML, femto TECH, Atmos-12D and AlphaGuard. Later, some more instruments
were evaluated and were added to the radon instrument inventory. Another category of continuous
radon monitors were solid-state detectors such as the Sun Nuclear Professional Radon Gas
Monitor Model 1023 and the Rad 7 developed at MIT. At present, a modified version of the Rad 7
is known as Durridge 7. The Rad 7 incorporated a pump and was the only active continuous radon
monitor with a solid-state detector. It used alpha spectroscopy and it had the capability to sort out
Po-218, Po-214 from Po-216 the first decay product of Rn-220.
In the third category, I listed the continuous scintillation cell monitors represented by the Pylon
AB-5 another active CRM that uses a pump to draw air through the scintillation cell continuously.
A second scintillation monitor manufactured by Pylon at the time was a passive unit requiring no
pump to drive radon through the scintillation cell. In 2012, I was informed by Pylon that the AB-5
is going to be phased out for a more versatile and more expensive device.
Another active scintillation monitor at the time was the Eberline RGM-3. I believe the Eberline
RGM-3 is no longer manufactured. I had a lot of experience with that device while I was using one
to monitor the EML radon chamber continuously. It was the most sensitive device on the market
because it was using a 3 Liter scintillation cell coupled to a 5-inch photomultiplier tube.
All continuous radon monitors provided the hourly and average radon concentration for periods of
2-3 days. For measurement periods from 2 up to 7 days charcoal collectors became the most
popular passive integrating devices. From 1979 when I first started using charcoal canisters to
measure indoor radon until 1994, many labs developed their own methods using charcoal canisters
and scintillation vials.
Canisters contain from 25-90 g of activated carbon. LS vials usually contain 2-3 g of carbon for
measuring environmental levels of radon. There were too many manufacturers and users to
mention. Probably, more than 70% of the short-term measurements at the time were conducted
with charcoal collector methods. A second passive integrating device for short-term measurements
was the Electret Ion Chamber known as E-PERM manufactured by Rad Elec. During the
development of this device I was asked by NY State to be an advisor to help in getting the device
suitable for field exposures. I believe, NY State was funding the development of the E-PERM. Rad
Elec. also developed a long term E-PERM using different thickness electrets that were suitable for
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exposures from 3 months to 1year. The Radon Testing Corporation of America RTCA developed a
long term electret ion chamber known as the Radome. The Radome was exposed in conjuction
with a second unit that measured the contribution of the gamma background radiation directly. The
E-PERM utilized the altitude at the test location to make a correction for the background gamma
radiation. .
A third passive integrating device for long-term radon measurements was the alpha track detector.
The principle of detection is based on the production of alpha tracks in solid-state materials such as
cellulose nitrate or CR-39 plastic films. Alpha track detectors were used primarily in Europe and
everywhere else except the United States. In the US, the technology was introduced by Terradex in
1981. Later a modified version was developed by Landauer as the main distributor of the device.
Several universities were developing their own versions. Today there are three manufacturers of
alpha track detectors in the US. Probably, <1% of the radon measurements in the US use alpha
track detectors because almost all radon measurements are driven by the real estate transactions
that require quick answers.
Radon decay product measurements are becoming rare these days but in the 1980’s were
used by many radon professionals for diagnostic purposes and in research activities. At that
time we used sophisticated methods for determining the individual concentration of the RDP and
simpler methods for determining their combined WL concentration. I used both methods in
uranium mines in the 1960s and 1970’s and in numerous intercomparison exercises with National
and International Labs or other radon professionals. The Canadians were always one step ahead of
the US when it came to WL instrumentation. Some of those instruments may not be manufactured
any longer. The Thomson/Nielsen for integrating sampling of RDP WL, the Pylon WLx for WL
and the Alpha Nuclear for continuous measurement of the WL were all Canadian. In the US the
Eberline WLM-1 besides EMLwas the only integrating WL instrument manufactured in the US.
Several radon professionals began to use them in the 1980’s. This instrument seems to be phased
out or is not manufactured any longer because 99% of the measurements today are for radon rather
than WL. More details about each test device are listed in the paper “Overview of State of the Art
for Measuring Radon/Thoron and their Progeny” authored by A. C. George and published in the
Health Physics Journal Volume 70, No. 4, 1996.
On June 27 through July 2, 1993, the first International workshop on Indoor Radon Remedial
Action –The Scientific Basis and Practical Implications was held in Rimini, Italy. It was held at the
Grand Hotel renown as a national institution in Italy. It was a classic luxury hotel near the water on
the Adriatic Sea.
One of its famous residents was Federico Fellini the top cinema director in Italy at the time. Fellini
was a native son of Rimini. In his movies he blended fantasy with reality. When he was making
movies he bypassed the script and improvised as he continued filming. He won an Oscar for the
best foreign language film “Dolce Vita” a bit controversial at that time but one of my favorite
movies in 1960. Two months after the radon meeting he suffered a stroke in the Grand Hotel. He
died in a hospital in Rome and was buried in his native city of Rimini.
The workshop was organized by the Commission of the European Community, US DOE, USEPA
and the Italian ENTEA. Because of the increased awareness of the potential health impact of
indoor radon, the scope of the workshop was enlarged to include biological and physical effects,
62
surveys and policy matters. Of the 81 presentations 78 dealt with radon and 3 were related to
thoron. As in the previous meeting in Capri in 1983, our hosts were gracious and very generous.
My friend Luigi Tommasino was instrumental for arranging for the 211 participants to spend 2
hours in a big winery to enjoy the large assortment of cheeses and wines. Later in the evening we
were treated to a great dinner in the banquet hall. A six piece band provided lively music and
entertainment during the farewell dinner. The proceedings were published in the Journal of
Radiation Protection Dosimetry Vol. 56, No. 1-4 1993.
In 1993, as a member of the International Organizing Committee I was invited to present a
paper at the International Workshop: Indoor Air: An Integrated Approach that was held at the
Australian Gold Coast in December 1994. Professor Lidia Morawska, the Workshop Chairperson
in less than a year’s time was able to put together a wokshop that dealt with so many indoor air
pollutants. Of the 114 presentations 23 wee related radon. The week before the Workshop at the
Gold Coast, half a dozen specialists in aerosol physics had an informal workshop at the
Queensland University of Technology in Brisbane Australia. Pofessor Morawska hosted the
workshop in her research laboratory in the School of Physics. Each participant gave a brief
presentation on the methods for measuring RDP in their respective countries. It was a useful
gathering resulting in recommendations how to address the topic in future studies. At the
conclusion of the special meeting, Lidia was very generous in hosting an outdoor barbeque dinner
in her home. For the first time, I was introduced to Foster beer a premium Australian beer. Thanks
Lidia. Your pleasant smile and your passion for your work ought to be admired. The following
week we drove from Brisbane for the Workshop: Indoor Air, an Integrated Approach at the Gold
Coast of Australia. My presentation in the session on Exposure Measurement and Standards was
one of the 23 papers related to radon issues. When I was asked to talk about the Status of radon and
RDP measurements in the US I chose to discuss the third Intercomparison of instruments and
methods for measuring radon and RDP in indoor air.
In 1994, EML was the only standards laboratory for RDP intercomparisons in the US. Prior to
1994, I hosted intercomparisons for smaller groups who had no other place to go for help.
In the 3rd intercomparison conducted from April 22 to May 2, 1994, in the new EML radon
chamber we hosted 23 private firms, government laboratories and universities who submitted 165
passive integrating devices consisting of charcoal collectors, nuclear alpha track detectors, electret
ionization chambers and 11 continuous radon monitors. Five groups participated in person to
intercompare their methods for determining the individual RDP concentration and the WL. The
results indicated that more than 80% of the instruments for radon determination were within ± 10%
of the reference value. To be more specific, the mean and standard deviation from the reference
value for charcoal collectors was 1.04 ± 0.10, for alpha track detectors was 0.96 ± 0.09 and for the
electrets was 0.97 ± 0.03. Among the charcoal collectors for radon those with diffusion barriers
produced the best results. Only one open face type charcoal collector for radon overesponded by
20%. Alpha track deviation ranged from 0.81- 1.10 whereas in a 1991 exercise, the range was
0.69-1.80. In 1993 the deviation ranged between 0.72-1.02. Obviously some people went back and
did their homework and came out with a better product in 1994.The mean from the reference value
for continuous radon monitors was 1.01 ± 0.05 indicating properly calibrated and maintained
instruments.
The measurements with continuous and integrating WL monitors showed ratios ranging from
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0.66 – 1.5. The instruments that measured on the low end suggest plate out of RDP that do not
reach the collection filter or due to inappropriate air volume or counting efficiency. The authors of
the report are A. C. George, K.W. Tu and E.O. Knutson.
The sixth International symposium on the Natural Radiation Environment was held in
Montreal Canada, Jun 5-9, 1995. This symposium was the last one before my retirement from
the US Department of Energy. The US DOE and EPA provided financial support along with
Clarkson University Potsdam, the Atomic Energy Control Board of Canada and the Health and
Welfare of Canada. About 300 scientists attended presenting 150 papers of which 105 were on
radon and another 5 on thoron. For the first time in my radon career I did not present a paper.
However, I had a small meeting with people who had or were planning to build radon calibration
facilities in their respective countries. Previously, I participated in a workshop hosted by the
Co-ordinated Research Program of the International Atomic Energy Agency in Cooperation with
the Commission of European Communities in Vienna Austria. We prepared a document for an
ideal radon chamber after I inventoried and gathered all the scattered information about the
existing radon chambers worldwide and tried to place them in a unified document for use during
the Vienna workshop.
During the banquet in Montreal NRE honored the late Wayne Lowder who was retiring from
DOE. As I mentioned earlier, Wayne was the key person in establishing the Natural Radiation
Environment Symposia. Wayne played a significant role in emphasizing the significance of
Natural Radiation. The complete story behind the establishment of the Symposia can be found in a
paper I wrote on the historical development of the NRE Symposia that I presented at the NRE VII
symposium in Rhoads Greece in 2002.
Susan Rose from the US Department of Energy Office of Health and Environmental Research
(OHER) did a fantastic job roasting Wayne during the farewell celebration. The proceedings of the
Symposium were published in a special issue of the Journal of Environment International
The week following the NRE VI symposium in Montreal EML hosted the Sixth International
Radon Metrology and Intercomparison Workshop. Thirty participants from 11 countries attended
to intercompare their measurement methods for Radon and Thoron concentrations and Radon
exhalation from a radium spiked concrete slab that I was using as a standard emanation source.
Field measurements included soil gas radon measurements and radon exhalation in New Jersey
soils. Adam Hutter, Earl Knutson and I prepared a separate report on the workshop findings.
The Fourth intercomparison of monitoring instruments for radon and RDP measurements
was conducted in the new 30 M3 Radon test facility to determine the performance and suitability
of these test devices to assess human exposure from radon and RDP. This program was different
from the US EPA RMPP. EML at the time served as the reference calibration facility in North
America and as such provided support to participants from the US, Canada, South America and
Asia. In the intercomparison exercise there were 13 participants that used open face and diffusion
barrier collectors, 10 with alpha track detectors, 9 with short-term and long-term electret ion
chambers, and 13 with active and passive commercial electronic continuous radon monitors. For
RDP measurements there were four participants that came to EML in person to take part in the
grab sampling methodology for measuring individual RDP and the WL. There were also 11
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participants with integrating and continuous commercial electronic instruments used for
measuring the WL. The concentration of radon in the test facility was about 25 pCi/L throughout
the test period.
The results expressed as the ratios of the Participant/Reference were:
Charcoal collectors ranged from 0.91-1.13 (average =1.02)
Alpha track detectors ranged from 0.69-1.25 (average = 0.96)
Electret ion chambers ranged from 0.88-1.35 (average = 0.98)
Continuous radon monitors ranged from 0.91-1.04 (average = 0.98)
The continuous monitors performed very well. Not long ago, some of them were plagued with both
high positive and high negative calibration biases.
Measurement concentrations of individual RDP and the WL showed good agreement with the
reference value even at low concentration of particle concentration indicating that by using open
face filters to collect RDP avoided plate out conditions. The results from the integrating and
continuous WL monitors show ratios ranging from 0.57 – 1.03 with 55% of the instruments within
± 25% of the EML reference value. It is obvious some of these instruments are affected by plate
out when used in environments where the particle concentration is <3,000 particles/cc, a condition
found in homes at nighttime. The paper authored by A. C. George, E. O. Knutson, K.W. Tu and I.
Fisenne was published as EML Report EML-577, December 1995.
As EPA assumed a more active role to address the radon problem in the US, the Department
of Energy my employer began to pull away from the radon issues. During my employ from
1963-1996 the AEC and later DOE were funding the radon program carried out at HASL and EML
and by many contractors and by several universities. For 33 years, I spent most of my time on
radon research and instrument development. Radon was the bread and butter for my family. My
work investigating radon in underground mines, AEC excess sites and in residential buildings was
one of the most exciting and rewarding experiences of my life. I enjoyed every moment even the
time I spent underground working in the harsh conditions of the mines. The rewards were too
many. I was given the opportunity to write and present papers in different forums around the
world. I was privileged to meet and interact with hundreds of colleagues worldwide. Also, I was
fortunate to work for a government agency that was somewhat independent from the federal
government. That independence originated with the establishment of the US Atomic Energy
Commission (AEC). The environment in which I worked for so long was conducive and
encouraging to conduct research on so many aspects of radiation. When the time came up to
undertake radon research, HASL was the ideal place to provide me the opportunity to work with
some of the pioneers on radon research.
Since the radon program was on its way out at DOE, I decided that it was the right time for me to
retire after 35 years with the federal government including two years in the US Armed Forces.
From 1987 until 1996, Nancy Bredhoff from the Radon Testing Corporation of America (RTCA)
kept coming to EML for spiking the RTCA diffusion barrier charcoal canisters on a monthly basis.
The EML radon test facility was made available and accessible cost-free to anyone who needed it
for QA and QC and spiking purposes. Nancy was a frequent visitor to EML to check on the quality
of radon measurements made with RTCA products. I was very impressed with the performance of
the RTCA charcoal canisters in the radon test chamber and in the field for short-term radon
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measurements even in environments where the radon concentration varied by more than a factor of
10 during testing.
When I decided retire in January 1996, I thought I may stay home and devote more time to my
hobby of farming and spend more time with my family and grandson. Well the thought of not
working with radon did not endure for long. Nancy who knew how passionate I was about radon
asked me to join RTCA for part-time consulting work to oversee the laboratory operations, train
radon measurement technicians and specialists and at the same time stay active in radon activities.
Three weeks after my retirement I was back doing the business of radon in the private sector. It has
been 16 good years now and I enjoyed and treasured each year. Nancy and I authored several
papers on radon, traveled to annual radon meetings and I even made two international radon
workshops. Thanks Nancy for helping me keep the passion for radon alive.
After a few months at RTCA, we decided that there was a need to simplify the method for
collecting radon in a vial containing a small quantity of activated carbon and use the scintillation
method for counting. We tried to simplify the LS method by eliminating some steps in preparing
the samples for analysis. We made the method more direct by eliminating the need for a desiccant,
sample transfer and the risk of sample degasification. We selected a 20 ml clear polyethelene
(PET) plastic vial containing 2 g of activated carbon with an airtight screw cap. During exposure
the screw cap is replaced with a second screw cap that serves as a diffusion barrier.
The LS vial can be used up to 7 days. Also the amount of water vapor diffusing through the
diffusion barrier is insignificant at a humidity of <50% and needs no correction of the calibration
factor. At higher humidity the method provides for the amount of water collected by weighing the
vial before and after sampling. The lower limit of detection is 0.25 pCi/L for a 4-day exposure with
analysis 3 days post exposure. The measurement error at 4 pCi/L is <8% when counted for 10
minutes. If both background and sample are counted longer the error is reduced accordingly. The
paper authored by A.C. George, Nancy Bredhoff and Jason Esposito was published in the
Proceedings of the International AARST Symposium held in Cincinatti Ohio, November 2-5,
1997.
A few months after I retired from DOE, I received an invitation from the Tohwa University
and Institute of Science to give a key-note presentation at the Symposium on Radon and Thoron
in the Human Environment to be held in Fukuoka Japan in October 1997. The trip to Japan and
hotel accommodation expenses were undertaken by Tohwa University. After a 14 hour flight from
Los Angeles I arrived in Tokyo where I spent one evening to adjust to the time zone change. The
following morning I took the famous speed train for Fukuoka. After some intermediary stops
including Hiroshima I arrived in Fukuoka which is half-way between Hiroshima and Nagasaki. In
the afternoon I went to the university to locate the Fukuda Minerva Hall the site of the meeting.
My paper, the first of the 83 presentations was “Instruments and Methods for Measuring
Radon/Thoron and their Progeny: Calibrations, Intercomparisons and Particle Size” In the paper I
attempted to give the audience an overview of the instrumentation used to assess the risk from
Radon/Thoron and their decay products. I described the methodologies, sampling and analysis. I
discussed short-term versus long-term measurements, grab, integrating and continuous sampling.
Since I was presenting an overview of the radon and thoron subject I discussed the different
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instrumentation for measuring their concentration and the current methods used to measure the
size of RDP. At the same meeting, Bernie Cohen presented a review of his paper on the Test of the
Linear –No Threshold Theory of Radiation Carcinogenesis. Our Japanese hosts were very
gracious and generous. They treated the participants to great evening dinners in exotic restaurants.
After the week-long meeting, I returned to Tokyo by train to attend a week-long radon workshop at
the Nuclear Center at Chiba near Tokyo airport. Our hosts were very generous providing the
workshop participants with cost free accommodations that were very comfortable with all the
amenities you find in luxurious hotels. They also provided us with all meals during the workshop.
There were short- presentations about the radon/thoron research done by the participants in their
respective countries. It was truly an International Workshop. Both places in Japan were worthy of
the long trip to reconnect with some of the international radon rangers that I interacted with for the
previous 35 years. I am writing about this meeting a month after Bernie’s passing. Bernie and I
spent quite some time at the Fukuoka meeting and took a tour of the city. Bernie was a true
gentleman and a dedicated scholar. He was a prolific author. His boyhood hero was John Lewis the
president of the Coal Miners Union. In 1978-1979, I developed the charcoal method for radon
collection and in 1983 Bernie visited me at EML to discuss the merits of using activated carbon for
collecting ambient radon. A few months later he wrote a paper on charcoal canisters and had it
published in the Health Physics Journal. He published more than 300 scientific papers on nuclear
power and on the health effects of radiation. Bernie had become one of the regular participants in
the DOE radon intercomparison exercises that I conducted in the radon calibration facility at EML
US DOE. Bernie was one of a kind and will be sorely missed by the scientific community.
At the Rimini meeting in 1993 and at the meeting at the Gold Coast of Australia I had the
pleasure to meet with Professor Simopoulos from the Nuclear Engineering Section of the
National Technical University of Athens. He had indicated to me that his University was interested
in hosting a Radon Workshop or mini symposium to be held in Athens for the first time. Because
of my long involvement in radon research and continuous presence at the NRE symposia he asked
my cooperation to help his group to undertake such an ambitious project. Of course my answer
was a profound Yes. Being fluent in Greek made my job very easy. First we decided on the title of
the meeting topic. We selected “Radon in the Living Environment” as seen by the European
Commission and the European Union Concerted Actions, European Research into Radon in
Construction. The meeting was held in Athens from April 19-23, 1999 on the same week NATO
airplanes were bombing the Yugoslavian Army in Kosovo. Security at the meeting was on high
alert. Fortunately, the meeting went along uneventful and was very successful. More than 215
scientists from 32 countries presented 170 papers.
At this meeting there were many young researchers from Eastern Europe an encouraging sign that
radon research in Europe was alive and well. The papers were all related to Radon covering
geology, metrology, retrospective measurement techniques, health effects, radon resistant new
construction, remediation, modeling and radon surveys. My invited paper presentation was on
“The Present State of the Radon Program in the United States of America”. In my presentation I
attempted to give the participants information on the current US Radon Program and in what
direction it was headed to accomplish its mission.
Our Greek hosts were very enthusiastic in undertaking such a heavy responsibility. They should be
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congratulated for a great meeting and for the great and delicious meals for the two nights out to
enjoy the food, drinks and Greek entertainment. During the lunch periods skewered whole lambs
were carved in front of your eyes to feast on. One night the entire group was bused to an outdoor
taverna where all kinds of lamb dishes were served accompanied by plenty of wine and beer. Eight
US participants who were at the meeting can attest to that. Greeks are well known for their
Philoxenia (being friendly and good to strangers). I am not sure if the Greek wine or the Ouzo had
anything to do with the announcement that our hosts volunteered to host the next NRE VII
somewhere in Greece. It takes a lot of preparation and great expense to host the regular NRE
symposia. Being true to their word, in 2002 they hosted the NRE VII in Rhoads Greece.
In the 1990s there was very little information about field experience with activated carbon
methods for collecting and measuring radon. Activated carbon collectors were used first by
yours truly beginning in 1979 and by others beginning in 1986 in government and private industry
radon measurement programs. Both the open face and diffusion barrier carbon canisters and liquid
scintillation vials were evaluated and listed by EPA after they passed the EPA proficiency testing.
In the late 1980’s there were some radon professionals that were misleading the public about the
accuracy of the charcoal methods for radon determination. The reason I wrote the paper “Field
Experience with Charcoal Canisters for Measuring Radon in Air”, was to set aside the myth and
the misleading information about the accuracy of the charcoal methods. The myth was perpetuated
for many years even while EPA developed and evaluated a diffusion barrier charcoal canister that
showed excellent results in both the laboratory and in residential buildings where the radon
concentration varied by more than a factor of 10 and the humidity ranged from 20% to 80%. The
US EPA however failed to publish the findings of their evaluation in the open literature that
reaches many radon professionals. Instead, EPA published the results of their evaluation in a
report in a condensed version (EPA 520/5-90-032, November 1990, titled Standard Operating
Procedures for Radon Measurement Using Diffusion Barrier Charcoal Canisters. I was privy to all
the tables and graphs produced by EPA but not included in the EPA report quoted above. The EPA
study was very similar to the one I conducted a year earlier at the Department of Energy and
reported in the Health Physics Society Journal titled as “An improved Passive Activated Carbon
Collector for Measuring Environmental Radon” In my AARST presentation at the 2000
International Symposium held in Milwaukee Wisconsin October 22-25, 2000, I presented field
data from diffusion barrier canisters used by DOE, EPA, PA DER and RTCA showing that they
integrate accurately at high humidity and under extreme variations of radon concentration.
The sensitivities of the diffusion barrier charcoal collectors ranged from 30-145 net counts/minute
per 4 pCi/L. The sensitivity of the RTCA L/S diffusion barrier vial with 2 g of activated carbon
was found to be 53 net counts/minute per 4 pCi/L. In comparison the sensitivities of the most
commonly used continuous radon monitors ranged from 0.17-7.6 net counts/minute per 4 pCi/L.
Because the sensitivity of CRMS is low, EPA recommended 60 minute counting intervals instead
of one minute. From this study, I found that properly calibrated open face charcoal canisters used
for 2-3 day exposures yield very accurate results.
As I mentioned earlier, our Greek colleagues from the Technical University of Athens
volunteered to host the NRE VII. The big undertaking took place on the beautiful, island of Rhoads
in May 2002. More than 110 papers from a total of 143 were related to radon and thoron. It was
clear from the quality and the diversity of papers that the study of the natural radiation
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environment was an active and continuously expanding field of research.
Since I attended all the NRE Symposia except the first one in 1963, I was asked to write a paper on
the historical development of the NRE Symposia. Also, working with Wayne Lowder for more
than 30 years at HASL US AEC and EML US DOE, was a plus for me. The idea for NRE
Symposia was proposed by Wayne Lowder who invited Professor John Adams of Rice University
of Houston to become a cofounder of NRE Symposia. At that time, AEC had a great interest in
studying natural radiation background and its variation to provide some perspective on the
significance of high levels of fallout in the environment. More importantly we came to the
conclusion that it would be desirable and beneficial to standardize methods and techniques to
obtain more accurate and detailed knowledge of the natural radiation base line of the human
exposure. Also, the founders of NRE felt that important data regarding natural radiation were
scattered throughout the literature of a number of science disciplines making access difficult. They
were looking forward to a unified source of information that could provide the tools and data to
assess more accurately the significance of additional radiation exposure from man-made sources.
In the invited paper I gave a brief description of all the NRE Symposia that became essentially
about radon/thoron and their decay products.
In the 1960’s, HASL US AEC embarked on a measurement strategy to define the extent of human
inhalation exposure from radon and radon decay products. I was fortunate to be involved heavily
in the characterization of uranium mine atmospheres from 1964-1976. From our underground
mine work, we provided data that were used in lung dosimetry for the accurate assessment of the
health risk from radon and RDP. As our underground mine studies were winding down we
embarked on radon measurements in indoor and outdoor environments. The NRE symposia
switched to environmental radon measurements with more than 1,000 presentations by hundreds
of radon professionals from the international community.
In my conclusion, I told the audience that we have come a long way since the first NRE
Symposium in 1963. From 1963-2002 thousands of pages of good science, new and useful
information were shared by two generations of radon rangers and researchers. I told the large
number of young participants that it is my hope that this trend continues in the future. Keep the
NRE series going for another 40 years and beyond.
At the same meeting, I presented a second paper that was similar to the paper I presented at the
AARST 2000 International Symposium. The paper, authored by A.C. George and Nancy Bredhoff
was addressing the wider international community. The paper emphasized the usefulness of
charcoal collectors for radon when results are needed in a hurry. It also showed that the charcoal
test devices are the most sensitive for short-term exposures (2-7 days) yielding the highest net
counting rate at radon levels of 4 pCi/L.
In 2005, I presented a paper at the 15th Annual International Radon Symposium held in
San Diego, CA September 25-28, 2005 titled “Intercomparison of the Sensitivity and Accuracy of
Radon Measuring Instruments and Methods”. The paper lists and compares the sensitivities of
different instruments and their principle of detection along with the cost. The cost of electronic
instruments with accessories range from $900 - $8,000 with the most popular between $2,000 –
$4,000. The cost of radon detectors or collectors analyzed by private laboratories is about $25.
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Unlike electronic devices the less costly passive test devices provide reliable and defensible results
because they undergo monthly spiking, duplicates and blanks for accuracy, precision and bias.
In 2006, Anselmo Paschoaa a retired Physics Professor from Rio de Janeiro and a
participant at many NRE Symposia, informed me that he volunteered to host the NRE VIII in
Busios, Rio de Janeiro, Brazil in October 2007. Anselmo, was an old friend and colleague and one
of the foremost experts on Natural Radiation. He wanted to present a balanced program at the
symposium the first of the Symposia series ever held in South America. He invited 150 scientists
from 24 different countries to present 175 papers. The meeting was very productive an example of
multidisciplinary effort in NRE research undertaken worldwide. Exchange of scientific knowledge
was shared by the attendance of young graduate students side by side with more experienced
scientists.
I was invited as keynote speaker to talk about a topic that was very dear to me. Since radon became
the primary subject for discussion at the NRE Symposia, Anselmo asked me if I was willing to
prepare a paper addressing the “World History of Radon Research and Measurement from 1900 to
2007. At first, I thought it would be difficult to gather the information covering the period from
1900 to 1964. With the advent of computer information access and from previous knowledge
about research in natural radiation by eminent European scientists in the early 1900’s I was
confident I would be able to cover the time period from 1900 through 1964. European research
conducted by the Curies, Dorn, Rutherford, Sody and Thomson was part of the classical physics
era that rewarded some of them with the Nobel Prize in Physics or Chemistry. From 1964 to 2007,
it was going to be easy to write about all aspects of the radon issue since I was involved in it full
time. My continuous work on radon and radon decay products was published and discussed in
more than 75 scientific papers authored by yours truly or co-authored by several colleagues at
HASL and EML.
Busios is about 90 miles from Rio. It is a resort coastal city that rich Brazilians use for vacation
away from the crowded beaches of Rio. I believe Brigitte Bardot visited the place in the 1970’s and
the city erected a small statue in her honor. There were many fine restaurants to choose from a
variety of fish or meat fare. Unlike Rio, we were advised that it was safe to walk around at night.
The drive from Rio to Busios was about 2 hours passing many pastures where thousands of cattle
were grazing. Now I know why Brazilian restaurants in New York serve several different portions
of beef at every meal. The meeting banquet dinner reminded me of Brazilian restaurants in New
York that serve several cuts of beef.
In my key-note presentation I was able to give the audience a synopsis of the history of radon
research and measurements from 1900 through 2007. I spent a lot of time getting the paper
together to organize it in some chronological order for the appreciation of the reading audience.
Here, I am discussing some of the highlights of my presentation. Radon professionals will derive
the most benefit by downloading the paper from one of the AARST publications.
In 1906, Rutherford suggested the adsorption of radioactive emanations on charcoal. That
particular suggestion helped me in the development of the activated carbon method for collecting
and measuring radon in air. Measurements of radon in the early years were conducted with
home-made electrometers, electroscopes and primitive ionization chambers. By 1947, the fast
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pulse ionization process began to appear being capable to measure very low levels of radon.
While studies were conducted to assess the health risk from radon and radon decay products,
measurements were made to characterize different environments such as radon in soil, building
materials ground water, caves, spas, underground mines and in residential and occupational
environments. Radon measurements were also used to study air masses, vertical diffusion,
earthquake prediction and atmospheric and geological studies.
Beginning with the mid 1960’s many measurement methods for radon and RDP concentrations,
their inhalation and particle size distribution were used worldwide. Today, the most commonly
used instruments for radon are passive devices for short-term or long-term measurements. They
include short-term activated carbon collectors, electret ionization chambers and long-term alpha
track detectors. In the last twenty years passive or active continuous electronic devices have been
developed as pulse or current ionization chambers, solid-state detectors and scintillation cell
monitors that produce hourly measurements.
NRE VIII in Brazil showed the importance of research in natural radiation ranging from astronauts
working in space to crews on board aircraft, residents in dwellings underground miners and tourist
guides in underground caves and spas. At the conclusion of the Symposium, some of our Japanese
colleagues expressed interest in hosting the 9th NRE Symposium in 2013 or 2014. That was before
the unfortunate accident and disaster at Fukushima. It is uncertain if our Japanese colleagues will
be able to undertake the task for NRE-9.
On February 9, 2011, I presented an invited paper at the Midyear Health Physics
Symposium in Charleston South Carolina. My friend Charles Roessler a 1970’s Florida Radon
Ranger convinced me that it was the right time to present a paper on the Current State of the Art in
Measuring Environmental Radon to the members of the Health Physics Society. He asked Phil
Jenkins also to present a couple of papers on radon standards. I believe there was a third presenter
on radon in the special session. Since I could not afford the registration fee for the meeting, I just
traveled to Charleston to present my paper and then returned to New York. Fortunately, RTCA
paid for my travel and everything went well. In my talk, I gave the audience a brief overview of the
US Radon Program and where it was going in the next few years. I talked about the use of
short-term radon measurements and what instruments and methods are commonly used to get an
average concentration value during a 2-7 day measurement period. I showed and discussed the
sensitivity of the different radon instruments so the user can decide which is most suitable for
deployment in their measurement program. To my surprise there were three radon measuring
instrument manufacturers who participated in the EML radon measurement intercomparison
exercises in the late 1980’s. I also reconnected with some colleagues from the Health Physics
Society who were involved in other radiation safety issues rather than radon.
As we are approaching the end of December 2012, I am still working two days/week as a
consultant in the radon arena. In January 2013 it will be 17 years since I retired from DOE. I will
keep working as long as I am able and remain current with any radon issues that may arise. During
the 1980’s I met many people who were joining the ranks of radon rangers ready to address the
radon problem that was becoming an important concern in the indoor air environment. Some of
these individuals had become prominent radon professionals conducting radon measurements and
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providing information how to fix the problem. In the past 17 years while at RTCA and through my
association with AARST and CRCPD, I remained active doing some research and train radon
professionals. I was fortunate to train hundreds of individuals who had become successful home
inspectors and mitigators to join the ranks of radon rangers. I believe I attended all AARST/EPA/
CRCPD annual meetings where I made lots of new friends and found new colleagues.
Bill Broadhead was one of the first radon professionals that I met in the mid 1980’s as the EPA
radon program just began to become reality. He brought his measuring equipment to DOE for
calibration and for intercomparison purposes before the EPA Radon proficiency program kicked
in. Bill made frequent trips to EML in New York to make sure his measuring equipment was
making accurate radon measurements. He is an enthusiastic and motivated experimenter always
ready to conduct tests in his laboratory (basement) to test his instruments and his ideas and
improve mitigation technology. More important is that he shared his findings with other radon
professionals at the annual AARST meetings where he presented papers and conducted
workshops. On many occasions we exchanged information on many radon issues. Bill is not only
an accomplished teacher and a radon mitigation specialist but also a good investigator willing to
share his knowledge with others ready to advance the evolving mitigation technology.
Leo Moorman like bill Broadhead is another investigator who uses his scientific background to
publicize the health effect of radon and advance mitigation technology with sound and scientific
technical explanations through his writings in the AARST proceedings and other journals. Leo
takes the time to respond to all questions related to radon issues. With good theoretical background
Leo is in the perfect spot to disseminate information in a clear and persuasive fashion.
Gary Hodgden became a close friend and colleague with whom I had many informal discussions
on radon standards and other radon concerns.
With John Mallon a fellow Pennsylvanian, I shared many discussions on radon. He is another
radon ranger who gets involved in disseminating information.
With Dave Wilson I shared many discussions on the science of radon in the early days of the
radon program.
Dick Manning is one of the first group of radon instrument pioneers that interacted with EML in
the development and evaluation of his company’s instruments. Dick manning is a true gentleman
and a friend.
Terry Howell another early radon ranger and instrument pioneer was one of the first radon
instrument developers that set up a radon chamber in Atlanta. He was one of the early participants
in the EML DOE radon intercomparison exercises. Terry, those were the good old days.
Bill Simon, another early radon ranger contributed in a big way to radon instrument development.
Mike Kitto is very generous with advice and volunteers his services for the sake of a sound radon
program. Mike usually presents 1- 2 papers per year at the annual AARST meetings providing
radon professionals with fresh and innovative ideas. I am particularly thankful for Mike’s efforts to
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provide radon standards for radon in water analysis.
I had the pleasure to interact and work with Paul Kotrappa on several radon projects. I appreciate
his enormous contribution to the science of radon. He helped the radon industry in its infancy in a
big way.
I like to thank Darioush Ghahremani and his family for their friendship and the radon moments
we shared in different annual AARST meetings. Darioush was one of the organizers and hosts of
the AARST meeting in San Diego California.
I am grateful knowing Jim Burkhart the director of the Western Regional Radon Training Center
and the Radon Measurement Lab for providing QA services to many radon professionals. Jim is a
charismatic and enthusiastic teacher scholar who helped to elevate the science of radon to a new
level. Thanks Jim.
I appreciate the work done by Bill Angell. He dedicated most of his academic career around
building science especially related to indoor air quality including radon. He provided training
courses and workshops for the prevention of lung cancer due to radon and improved the health of
the general public from indoor air pollutants.
Finally, I like to thank Pat Everett the Radon Reporter Editor for her impartial reporting the radon
news no matter where the source is.
Now I like to express my appreciation to the following individuals who volunteered their time and
expertise to safeguard and secure the quality of radon measurements and mitigation.
Ray Johnson was the key person to suggest and propose the establishment of the National Radon
Safety Board (NRSB). He envisioned an association made up of radon experts who were willing to
volunteer to serve as members of NRSB. One of the most interesting times after my retirement was
when I was asked to volunteer and join the NRSB Board. The structure of the NRSB proposed by
Ray Johnson was based on the model of the American Board of the Health Physics Society. As a
Fellow member of the HPS, I made up my mind very quickly because I thought it would be
worthwhile for me to keep current on radon issues. The NRSB Board except for an executive
secretary depends entirely on volunteers with responsibilities in the health concerns, measurement
and control of radon. The members of the Board are radon professional from the public and private
sector with many years of experience in the radon field ready to provide the highest assurance that
the public interest will be protected at all times. The expert members of NRSB decide on matters of
policy and provide their services on a volunteer basis. The structure of the NRSB Board assures
the lowest costs for the radon program with direct benefits to the radon industry and the
community it serves.
Ray Johnson deserves all credit for proposing the establishment of NRSB to take over some of
EPA’s responsibilities after the privatization of the radon program. He approached Nancy
Bredhoff, Phil Jenkins and I to join him to form NRSB by bringing some more volunteers who
were willing to spend some of their valuable time to form, run and oversee the operation of NRSB.
Ray has one of the foremost background on radiation research, radiation safety and radiation risk
analysis. He comes from government service, academia and from the radon industry. He was also
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a founding member of the radon section within the Health Physics Society of which I am also a
member. I have great respect for his enthusiastic approach to any radiation topic. He brought into
NRSB a long and distinguished career as a certified Health Physicist, a past president of the Health
Physics Society and as a professional in radon measurement, quality assurance and training.
Nancy Bredhoff, another member of the NRSB Board has extensive experience in radon
measurement and control. Coming from the radon industry she has administrative experience and
acquired radon expertise. She heads RTCA that researches and manufactures and distributes a
variety of radon test devices. She runs one of the most advanced analytical laboratories and
maintains RTCA’s nationwide network of professional radon testers. Nancy with an MBA degree
from Columbia University mastered the science of radon. She is a great administrator and a
certified Radon Specialist involved heavily in the radon program since 1986. I admire Nancy’s
work ethic and her zeal and passion for anything that has to do with radon.
I have great respect for William Bell another member of the NRSB Board of directors. He came to
NRSB from the state government sector with extensive experience in radon testing and mitigation.
As a member of the Conference of Radiation Control Program Directors (CRCPD) he manages the
Massachusets state radon program and provides consultation and technical assistance to
consumers, radon industry and local, state, and federal agencies.
Paul Houle, a retired Professor of Physics came to NRSB Board from academia. He continues to
be actively engaged in radon research and training. A dedicated radon ranger he developed
training courses for radon for continuing education purposes which are second to none. He has
lectured extensively on the topic of radon and presented many papers at international symposia on
radon. It is a great pleasure to know and work with Paul and enjoy our glass of red wine whenever
we happened to go for dinner.
Stephen Shefsky joined the NRSB as a radon expert who worked for many years in a research
facility that developed laboratory based methods for measuring radon in air and water. Stephen
designed and developed portable electronic radon instrumentation, and designed and operated
radon chambers and calibration systems. Stephen is a superb administrator and top radon research
scientist.
Christopher Juliano, brings with him a wide range of experience in analytical laboratories. He is
a prolific writer of standard operating procedures and addresses all details and requirements for
radon professionals, businesses laboratories and radon chambers. He provides technical support to
small businesses, particularly the radon industry. NRSB is fortunate to recruit him to volunteer his
services.
Finally, I like to thank Michelle Wunderlich the Certification Coordinator for NRSB. Michelle is
the executive secretary that administers the certification program for NRSB. She deals with
hundreds of radon professionals, businesses and laboratories. Michelle, is a diligent worker that
keeps the business of NRSB running smoothly in a timely fashion. She is a great asset to NRSB.
I’d like to acknowledge the radon rangers and colleagues from the Symposia. It was a privilege to
know them and work with them for more than four decades:
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Starting from the UK: J. Miles the late Anthony James, J.Strong, K. Cliff and Mike O’Riordan
were close collaborators and the original British radon rangers.
Many thanks to Jim McLauhlin from Ireland an early radon ranger and a guiding force in
organizing several NRE Symposia and Workshops. Together with the late N. Jonassen from
Denmark they made a good radon team. Going to Belgium I like to thank J.Sinnaeve who was the
main driving force behind the memorable Capri and Lisbon meetings that brought the Natural
Radiation Environment meetings to Europe. Also thanks to H. Vanmarcke for his innovative
presentations.
Going to France thanks to Madelaine and his colleagues for sharing their radon research findings
in underground mines in the mid 1960’s. In Spain I like to acknowledge L. Quindos who
exchanged lots of information on Scintillation cells for measuring environmental radon.
Moving to Italy, I made many friends. Thanks to Luigi Tommasino (Paisan), F. Sciochetti, S.
Risica and G. Campos Venuti. I will never forget the excitement and the camaraderie we had in
Capri and Rimini.
In Germany many thanks to J. Porstendorfer, the late A. Reineking and J. Jacobi for their
significant contribution to the science of radon. Thanks go to A.Wicke, G. Keller, T. Streil and
J.Schmitz.
In Austria, I was associated for many years with F. Steinhausler who was one of the key
Organizers of most of the Symposia and Workshops on radon. Thanks Fritz.
In Greece I was privileged to help a little S. Simopoulos, N. Petropoulos, Hinis and Anagnostakis
when they undertook the difficult task to organize two radon meetings both crowned with success.
They were such great hosts. Thanks to C. Papastefanou and his family with whom I shared many
Greek holidays and exchanged information on the radon programs in the US and Greece.
.
In Norway, I had close working relationship with E. Stranden and Terje Strand. They were both
enthusiastic radon rangers. In the late 1970's, I had the privilege to work with the following radon
rangers from Sweden; G. S. Swedjemark, R. Folk, Chris Samuelson and the late G. Akerblom. I
believe they were the first Europeans to address indoor radon.
I like to express my appreciation and friendship to my colleagues from the Far East and Australia.
Thanks to S. Tokonami, Y. Ikebe, M. Shimo, K. Fujimoto and T. Kobayashi. In China, I like to
thank Ching Chen who spent some time at our laboratory intercomparing methods of measuring
size distributions of radioactive aerosols.
Going to Australia, I like to thank Lidia Moawroska for inviting me to Brisbane and the Gold
Coast to participate at the radon workshop she organized at her University and also attend the
meeting in the Gold Coast area. I will always be indebted to her for her hospitality. Going further
south to Melbourne at the ARL thank you Steve Solomon. Steve, one of the original radon rangers
and I, traveled to several places to present papers and intercompare methods for measuring radon,
radon decay products and their particle size distribution.
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Now I like to return to America and acknowledge those who worked with me at HASL, USAEC
and later at EML, US DOE. But first I like to thank my Canadian friends who made uranium mines
accessible to me to start my radon career. Both the late G. Stewart and D. Simpson were very
generous with their time making it possible for me to conduct my first study in an active uranium
mine in 1964-65. In the 1980’s I got to know Arthur Scott and R. McGregor two fine gentlemen
and experts in their respective fields. Going to South America, many thanks to Anselmo Paschoa
who invited me to present a key-note paper at the 8th NRE in Brazil. Anselmo is another early
radon ranger. Besides being a good scientist he is a great dancer. He was really great at the farewell
dinner in Capri in 1983.
In the US, I met and worked with many radiation specialists especially with those involved in
environmental radiation. Beginning in 1964, I had the privilege to work with Wayne Lowder from
HASL, and J. Adams and T. Gesell from the University Houston Texas. They were the key persons
who came up with the idea of the NRE Symposia. They had become interested in studying natural
radiation background and its variation to provide some perspective on the significance of the high
levels of fallout in the environment.
As the number of NRE symposia increased the interest in radon as a major source of background
radiation increased too. I guess I was lucky to start my radon career in 1963 during the first NRE
symposium that began to address some of the issues raised by Lowder and Adams.
I have so many colleagues and coworkers to acknowledge and I apologize if some names slipped
from my memory. Starting in Florida, where I conducted small radon surveys and measured radon
emanation measurements from soils I am thankful to the Roesslers. In Alabama, it was a pleasure
to work with the EPA personnel; Ed Sensitaffar, Charles Porter, Sam Windham and David Gray.
They were a nice bunch of hospitable people. They introduced me to fried okra. We intercompared
methods for measuring radon and radon decay products and discussed the construction of radon
chamber facilities. Too bad EPA shut down the radon calibration facilities that these men took
many years to set up to serve the emerging radon industry.
In Texas besides Adams and Gesell I am very thankful to the late Howard Prichard who developed
the liquid scintillation method for measuring radon in air and water. Going West to Grand Junction
Colorado, I had the privilege to interact with the late Tell Tappan (T2), Hal Langner an early radon
ranger, K. Schiager, R. Holub D. McCurdy and the late D. Martz. My group at HASL worked very
closely with these Colorado radon rangers in uranium mines and in the laboratories. Going South
in New Mexico I had the privilege to work with the late Marvin Wilkening (who was one of the
Manhattan Project Scientists) and with Steve Schery measuring radon emanation and radon decay
particle size distribution in Socorro New Mexico.
I had the privilege to work with some of the LBL people in California. Thanks to Tony Nero, W.
Nazarof and R. Sextro. Together they formed a formidable team that left its legacy to this day.
Perhaps not many people know the amount of work done on radon by Otto Raabe while at the
University of Rochester. My first exposure to the subject of radon was through Otto’s PhD thesis.
It is original and innovative research on radon. Many thanks to Otto and the late T. Mercer at the
University of Rochester for their pioneering work on radon in the 1960’s.
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Many thanks to NY University radon pioneers such as the late M. Wrenn, W. Van Pelt and one of
my mentors the late Merril Eisenbud. Going to MIT, I had the privilege to interact with the likes of
the late Robley Evans, R. Kolenkow and G. Schroder who did some of the theoretical work on
uranium mine characterization. Their work was published in the famous handbook on “Radium
and Mesothorium Poisoning and Dosimetry and Instrumentation Techniques in Applied
Radioactivity. The handbook was published in 1968 as an MIT annual progress report
(MIT-952-5). In the report they included an entire section on uranium mine dosimetry and
radiation control. (pages 31-410) Every radon researcher who is going to do research in
underground mines will benefit greatly. Robley Evans had the unique gift of making things so easy
and comprehensible in his writings. His famous saying was “A little contemplation saves a lot of
calculation. The MIT group and A.Tanner from the US Geological Survey group made important
contributions to the First NRE Symposium.
Several managers from state radon programs worked closely with my group during the
establishment of the radon program. Thanks go to J. Eng in New Jersey and R. Lewis in
Pennsylvania. I appreciate their close collaboration in all matters of radon.
Now I’d like to return to my own laboratory that served as my home away from home for 34 years.
I was fortunate to work with some of the top people in the field of radiation physics, engineering,
radiochemistry and health physics. The laboratory’s mission was to collect information through
research and measurement and assess the health risk from radiation exposure.
John Harley director of the Health and Safety Laboratory (HASL) of the US AEC, was the most
experienced and knowledgeable person on radon. John with Bale were the first to state that the
radon decay products cause cancer rather than radon. John Harley also directed HASL personnel to
address the needs of the AEC and its contractors whenever an issue about radiation exposure came
up. Naomi Harley, initially employed at HASL was a great inspiration to me always available for
assistance. She is probably one of the foremost experts in the field of radon measurements and
dosimetry. Even to this day, I often contact Naomi for her guidance and counsel. Naomi was one of
my mentors. Her work ethic and collaboration influenced and enriched my own work. Thanks
Naomi. I had the great privilege to work very close with Isabel Fisenne for my entire 34 years at
the laboratory. Isabel, a top radiochemist was the premier operator of the HASL pulse ionization
chambers for radon measurements. The chambers served as the radon Standard measuring lab for
America and the rest of the World from 1981-2000. Isabel and I conducted the National and
International radon and radon decay product intercomparisons for 15 years using the pulse
ionization chambers and the radon chamber calibration facilities. I believe, we contributed
enormously to the radon community by calibrating and evaluating free of charge their instruments
and methods and gave them the confidence to go out to conduct quality measurements. Isabel’s
pulse ionization chambers served as the Radon Standard for more than 40 years Thanks Isabel for
being a radon partner for so many years. Thanks Helen Keller the third member of the trio who
devoted so many years checking the quality of radon measurements.
In the Health Protection Engineering Division of HASL, I was privileged to work under the
guidance of the late Alfred Breslin the division director. He was truly a good scientist and prolific
writer. He encouraged me to undertake new challenges. When the radon exposure of miners
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became an issue he entrusted me to go and investigate the conditions of exposure in underground
uranium mines. Working with Alfred was a privilege. We coauthored several papers in the 1960’s
on the measurements my team-mates and I conducted in a Canadian mine and at the laboratory in
New York to characterize radon and radon decay product atmospheres. At the same period I had
the privilege to work with J. Thomas and Phil LeClare. From them I acquired my knowledge of
aerosol physics which had become very useful later when I measured the particle size distribution
of radon decay .
Many thanks to Larry Hinchliffe who was the essential partner in all my trips to several uranium
mines in Canada, Colorado, New Mexico and Utah. Larry was a good friend and colleague. He
was very well versed in all aspects of measurements in underground mines. His expertise in
aerosol science and his computer skills became essential in the calculation and evaluation of
thousands of field measurements. Thanks go to Ron Knuth, the cascade impactor specialist and the
key man in some of the work we undertook in uranium mills. Also, I like to thank Ron for his
team-work effort in our 1967-68 uranium mine studies.
Earl Knutson came to work at EML in the late 1970’s. He became the director of the Aerosol
Studies Division a good thing for our laboratory because at that time we were into characterizing
radon decay product particle size distribution. He brought new ideas and new innovations that
improved the diffusion battery method for submicron size determination. I think of that time as the
classical era of diffusion batteries and wire screen methods for measuring unattached and attached
radon decay products. Earl Knutson, K. Tu and I, we characterized outdoor and indoor radon decay
product sizes and co-authored several papers that appeared in the J.of Aerosol Science, the Health
Physics Journal and several special issues of the proceedings of the NRE Symposia.
In the 1980’s Adam Hutter joined our lab and became our newest radon ranger. I had the privilege
to work with Adam and Mark Maielo on top of Mauna Loa in Hawai. Adam performed all the
daytime radon and RDP measurements alone while Mark and I conducted the nighttime
measurements.
I had the privilege to interact with Andre Bouville, in matters of uranium miner radon exposure.
His comments and observations were very useful when we began to address the uranium mine
conditions of exposure. Otto White while at HASL began the development of a uranium miner
dosimeter. He put teams together to go underground to test the personnel dosimeters. My task was
to be a member of one the measurement team and provide radiation safety for HASL employees.
After Otto left HASL for the Brookhaven Lab, I continued the evaluation of the dosimeters and
adapted them as radon decay product WL integrating devices to be used in several countries for
measuring the radon impact from different sources.
David Sinclair came to DOE after he retired from the John Mansville Co. Being an aerosol physics
specialist (Columbia University during World War II), he helped the lab in building several
versions of diffusion batteries. I was assigned to test them and later used them to measure the
particle size distribution of radon decay products. The results of measurements that I made in the
mines in 1971-72 for particle size distributions were used by the BEIR committee to arrive at a
dose conversion factor for uranium miners. David the son of Upton Sinclair retired from DOE
when he was 82 years old. We shared many lunches together. He told me about his father who died
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at the age of 91 and wrote 91 books. I missed his father’s funeral due to an overseas assignment at
the time. Upton Sinclair also ran unsuccessfully for governor of California in the 1930s. Two years
after David retired from DOE he died from asbestosis that he may had developed while doing
research on the automobile brake linings at John Mansville.
I’d like to acknowledge the mentoring of K. Obrien the HASL and EML cosmic radiation expert
and Harold Beck who was always there for me for guidance. Carl Gogolak offered unsolicited
advice and guidance. Kevin Miller and Al Cavallo who came into the radon program in the late
1980’s were great co-workers with fresh and innovating ideas. Thank you all for your consistent
support.
The instrumentation division provided logistical support and build most of the instrumentation
usedin my radon studies. Thanks to the late V. Negro, S. Watnick and I. Haskel. Thank you
Norman Latner and all the electronic technicians and machinists. It was very convenient for me to
walk 30 meters and step into a well run machine shop and observe the ongoing progress on any
instrument needed for my studies.
I had the privilege to work with Phil Jenkins on several occasions in the early 1980’s when he
managed the group at Mound Labs that developed monitoring instrumentation and methods for the
purpose of monitoring and characterizing several AEC, Excess Sites associated with the radon
remedial action. Later Phil set up a private secondary radon calibration facility at Bowser/Morner
that provides quality assurance for the radon industry. While I was working at DOE Phil and Jim
Short were two of the regular participants in intercalibration and intercomparison exercises for
radon and radon decay product measurements. Phil, with his long involvement with radon issues,
has become the latest Guru for radon. Phil and I attended all the AARST/CRPCD/EPA meetings
since their inception and shared all those radon moments.
I was privileged to work with two early stars from the State Radon Programs. Janet Eng from the
NJ DEP cooperated in so many ways for the benefit of the radon programs at DOE and in New
Jersey. Bob Lewis from the PA DER is a great resource in the radon program. I consider him along
with Phil Jenkins as the most knowledgeable radon workers.
Finally, I’d like to acknowledge the invaluable assistance and encouragement of Geoff Bolen who
helped with the layout and design of this book. Thanks, Geoff, for your patience and enthusiastic
approach in presenting the Adventures of Radon Ranger
In my spare time, I am doing a little farming in the summer. I am about finished writing my
second book that has no connection to radon. I will keep working as long as I can to do the work of
radon. I hope that I can continue to do some research work on radon measurement. According to
EPA, 21 million radon measurements were made in the US. About 75 million homes never tested
for radon. Lots of work remains for radon professionals. About 1 million homes have been
mitigated with another 5-6 million that need to be fixed. There is plenty of work for mitigators. We
must keep publicizing the radon problem in the US and get EPA to recognize and classify radon as
a primary and important indoor air pollutant.
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