I
I
CALIFORNIA STATE UNIVERSITY, NORTHRIDGE
PHENOLIC ASBESTOS
"
AN INDUSTRIAL HYGIENE ANALYSIS
A thesis submitted in partial satisfaction of the
requirements for the degree of Master of Science in
Health Science,
Environmental Health
by
--
Thomas Allen Beckett
June, 1976
The thesis of Thomas Allen Beckett is approved:
California State University, Northridge
June, 197 6
ii
-- -----------·-------------------T.Al3iEoF -co~:ff:E&'l:s--~--------------­
Page
ABSTRACT
v
CHAP':FER
1.
INTRODUCTION
2.
HEALTH EFFECTS RELATED TO ASBESTOS
Pathogenicity
4
Epidemiological Studies
6
Toxicology .
3.
4.
1
.
• .
.
.
.
.
12
Determination of Disease .
17
Asbestos Health Standard
19
PRELIMINARY SURVEY
Purpose
22
Phenolic Asbestos
23
Identification of Potential Risk
Areas
23
Employe Medical Histories
27
MATERIALS AND METHODS
Instrumentation
29
Sampling Strategy
32
Environmental Sampling .
35
Sample Preparation .
39
.
Microscopic Analysis
5.
RESULTS
Concentration Levels .
6.
7.
40
.
.
.
.
.
.
.
47
DISCUSSION
Exposures
51
Evaluation of Sampling and Analysis
Methods
. . . . . . .
• . .
53
CONCLUSIONS AND RECOMMENDATIONS .
64
REFERENCES .
68
APPENDIX .
71
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LIST OF TABLES
Table
l
2
Page
Expected and Observed Deaths Among 17,800
Asbestos Insulation Workers in the United
States, January l, 1967 - December 31, 1971 .
9
Expected and Observed Deaths Among 17,800
U.S. and Canada Asbestos Insulation Workers,
January l, 1967 - December 31, 1971 . . . . .
ll
3
Expected and Observed Deaths Among 370 New York
and New Jersey Asbestos Insulation Workers,
January l, 1963 - December 31, 1971 . . .
13
4
Mine Safety Appliances Monitaire Sampler
Model G Approvals and Specifications
29
5
Phenolic Asbestos Atmospheric Measurements
48
6
Results of Phenolic Asbestos Atmospheric
Measurements Analysis . . . . . . . . . .
49
LIST OF ILLUSTRATIONS
Figure
l
Phenolic Asbestos Material Flow Chart .
25
2
Asbestos Sampling Ticket
37
3
Asbestos Count Record Sheet
41
4
Reticle Calibration Worksheet .
42
5
Representative Microscope Field Area at
1500 X
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
45
Phenolic Resin Dust and Chrysotile Asbestos
Dust ( 15 0 0 X ) • • •
• • • • • • • • •
59
7
Phenolic Resin and Asbestos Clump (1500 X)
60
8
Aggregate Clump of Splintered Asbestos
Fibers (1500 X)
. . .
. ..•..
61
Non-Asbestos, Blunt Ended Fiber (1500 X)
62
6
9
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iv
ABSTRACT
PHENOLIC ASBESTOS
AN INDUSTRIAL HYGIENE ANALYSIS
by
Thomas Allen Beckett
Master of Science in Health Science, Environmental Health
Air sampling was conducted at an industrial firm in
Newport Beach, California, for six months during 1975.
The
membrane filter sampling and analysis method approved by
the National Institute for Occupational Safety and Health
(NIOSH) was utilized.
Concentrations of asbestos fibers greater than
5 microns in length per cubic centimeter of air sampled,
were mostly below 5 fibers per cubic centimeter.
Some
.concentrations, particularly those for sawing operations,
greatly exceeded the 5 fibers per cubic centimeter value.
Measured concentration levels for all operations were
compared with employe medical histories to determine if
health effects known to be associated with asbestos exposure were occurring.
In many instances evidence of health
v
--·-----changes such as reduced vital capacities and hilar calcifications were shown to exist among employes in the study
group.
The membrane filter sampling and analysis method
proved to be easy to learn and readily adaptable to most
situations encountered in the field and laboratory.
Most
importantly, the sampling and analysis methods were highly
reproducible once experience with the methods was gained.
The data gathered indicate a need for the implementation of a comprehensive industrial hygiene sampling and
control program, particularly for the sawing operations.
It is recommended that routine physical examinations and a
training program be initiated for employes required to work
with phenolic asbestos.
Local exhaust ventilation controls
for the sawing operations is necessary to reduce airborne
asbestos dust concentrations below legally prescribed
limits.
vi
@
CHAPTER 1
INTRODUCTION
Asbestos is a generic term that is used to identify a
number of naturally occuring fibrous hydrated mineral silicates.
These fibrous silicates when processed, are sepa-
rated into flexible fibers which can be spun, woven, or
pressed into a wide variety of products.
Since asbestos
is practically incombustible, most of these products are
used to insulate materials from high temperatures and
flame.
Modern technology has made asbestos almost
indispensable.
The commercially important forms of asbestos fall into
two distinct groups.
Chrysotile asbestos is mined primar-
ily in Russia and Canada which account for nearly all of
the worlds production.
main types:
The Amphiboles, consist of three
Amosite (Amber), Crocidolite (Blue), and
Anthophyllite (White).
The Amphiboles differ in chemical
composition from one another, but their molecular structures are very similar.
The world's annual production of asbestos has grown
from a few thousand tons in 1900, to over 3 million tons in
1968 (National Academy of Sciences, 1971) .
Annual consump-
tion in the United States is almost 1 million tons.
Of
this total, approximately 75 percent is used in the construction industry while 25 percent is used in non;
i
:construction related industries (NIOSH, 1972).
'---·-----··-·-----------------------1
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Asbestos has long been known to cause illness among
workers handling the material for extended periods of
'time.
Since widespread use of asbestos has steadily
increased, ambient levels and incidences of asbestos disease in the non-occupationally exposed have also increased.
Because asbestos related diseases usually do not
appear in "normal" healthy human beings until 15-20 years
after the onset of exposure, incidence of asbestos-caused
diseases was not studied extensively until the passage of
the Occupational Safety and Health Act in 1970.
Since that
time, studies and research indicate that asbestos exposures
have been excessive and lethal in the occupational setting
and quite possibly the general community as well.
This analysis will concern itself with the fabrication
and machining of phenolic asbestos to determine if exposures to phenolic asbestos constitute a hazard to workers'
health.
An industrial hygiene analysis of operations using
phenolic asbestos should provide information relative to
the current levels of workers' exposure.
Along with this
analysis, reviews of exposed workers' medical histories
should help determine if a causual correlation between
exposure and clinical symptoms or disease exist.
Should excessive levels of airborne asbestos fibers be
found and/or a correlation between exposure and clinical
:symptoms suspected, a comprehensive plan which will provide:
!
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-----·----·---j
3
for protection of employes' health and control of the
suspected operations will be recommended.
·-----
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CHAPTER 2
HEALTH EFFECTS RELATED TO ASBESTOS
Pathogenicity
Since the early 1900's, when asbestos was first susp~cted
of causing illness and disease in persons occupa-
tionally exposed to it, numerous research studies have been
done in an effort to identify the pathogenic effects of
exposure to asbestos.
Although results of past and present
studies indicate that asbestos is a carcinogenic agent, it
has never been proven whether asbestos is actually the
primary carcinogen.
The severity of pathogenic effects is directly proportional to the severity of exposure.
The severity of
exposure is dependent upon many factors such as; the type
asbestos, quantity of fibers, length of exposure and
presence of "co-factors."
The two major types of asbestos (chrysotile and the
amphiboles) display a definite difference in the amount of
dust (asbestos is considered a dust) that is retained in
the lungs of exposed individuals.
Timbrell (1965) has
shown that the fibrous dust of the amphiboles is retained
six times greater by the lungs than that of chrysotile.
Timbrell related this phenomenon to the aerodynamics of the
two mineral fiber types which he said, "accounts for the
deposition and clearance of particles in the pulmonary
4
5
chrysotile fibers are curled, much like stretched coils.
Because of their ''lesser" ability to penetrate the bronchial paths, chrysotile fibers should rarely be found near
the pleura (the endothelial lining of the thoracic cavity)
and hence be less likely to cause acute pathogenic effects,
such as the rare form of cancer called mesothelioma.
Asbestos fibers occur naturally with impurities and
other mineral fibers.
These impurities (often called
"co-factors") are suspected of contributing to the carcinogenicity of asbestos.
The impurities include:
brucite,
magnitite, magnesium carbonate, polynuclear hydrocarbons
(some carcinogenic), manganese and carcinogenic trace
metals such as nickel, chromium and cobalt (Dixon, 1970).
Another suspected, but little known fact is that
fibers of asbestos, once in the body, breakdown into much
smaller units called fibrils.
These fibrils may be hollow
inside and, therefore, act as capillary tubes which could
take up other "co-factor" materials (AIHA Symposium, 1972).
It has been shown that these fibrils are capable of migrating and becoming semipermanent implants in the peripheral
pulmonary tissues as well as the peritonium.
implants then may act as a tissue irritant.
These
Assuming
fibrils are broken down, the fact that they contain suspected carcinogenic co-factors makes them a potentially
greater health risk.
The proven pathogenic effects of asbestos on those
:persons occupationally exposed to it (particularly for long
6
periods of time), include non-malignant changes such as
fibrosis of the bronchial and pleural tissues and several
types of cancer, most notably of the lung, pleura and
peritonium.
Asbestosis, a recognized dust-related pneumonoconiosis, is usually characterized by fibrosis and calcification.
of the pulmonary pleura, along with most other physiological changes that are evident with other restrictive lung
diseases.
The incidence of lung cancers associated with asbestos
exposure is high.
Rare cancers of the pleura, known as
mesotheliomas, appear to be specifically illicited by exposure to asbestos.
Asbestosis is an insidious disease which usually does
not appear until twenty to thirty years after initial exposure.
It is an incurable disease which slowly incapacitates
the person who has it.
Once detected the individual may
be removed from the hazardous environment, but can only be
maintained at the level of health he was at when removed
from the hazardous environment.
Epidemiological Studies
The first published mention of a restrictive lung disorder in relation to an asbestos worker was by H. Montague
Murray in 1907 (National Academy of Sciences, 1971).
A
second and third case were later reported by Cooke, who in
7
i-9 2 7 ---:E :C~s-F--useCi ___ti~e-··t:erm--,;·a 8I;-e-sto
;
5Ts·;·,---fo--i2fei1t:I£y·-crrse-a.·s-e -- ·--
associated with exposure to asbestos.
The first suggestion that asbestos might be the cause
of lung and other cancers came in 1935 from Lynch and Smith,
who described carcinoma in the squamous cells of the lungs
'in a South Carolina textile worker with asbestosis.
:
It was not until several years after Lynch and Smith's ·
"suggestion," that an association between lung cancer and
asbestos exposure was firmly supported by epidemiological
evidence.
E. Merewether, Chief Inspector of Factories in
Britain, reported 31 instances of lung cancer in 235 persons
who were known to have died of asbestosis between 1924 and
1946.
A comparison with persons who were known to have
died of silicosis in the same period showed that 1.32 percent had lung cancer in the silicosis group and 13.2 percent had lung cancer in the asbestos group (Merewether,
1949).
As other epidemiological studies were conducted, it
became apparent that exposure to asbestos was not only
associated with lung cancer alone, but with many types of
other malignancies.
These other malignancies were detected
because they occur so rarely in the "normal" population.
Cancer of the pleura and peritoneum, known as mesothelioma, were regarded as excessively rare tumors until
recently.
The occurrence of any of these tumors in speci-
,fie occupational groups, therefore, make them statistically
significant (Cooper, 1967).
_ _ _ _ _ _.l
8
Q
In a study of asbestos insulation workers from 1967
to 1971, Drs. Selikoff and Hammond produced some startling
data shown in Table 1.
Of 17,800 men observed, no mesothe-
liomas were statistically expected.
Seventy-seven men,
however, died in a 5 year period of pleural and peritoneal
mesotheliomas.
No expected deaths should have occurred
from asbestosis, but in the same time span 78 deaths
occurred.
Significant numbers of other cancers are shown
which indicate that asbestos may be associated with their
origin (AIHA Symposium, 1972).
An epidemiological study was performed on 76 case
files of mesothelioma at a London hospital by Newhouse and
Thompson in 1965.
Their study revealed that of the 76
cases of mesothelioma, 31 had worked with asbestos and 45
had not.
Of the 45 who had not, 9 had lived with asbestos
workers and 11 had lived within a half-mile or less of a
London asbestos plant.
These and other epidemiological studies clearly
established asbestos as a carcinogen or carcinogenic agent
for cancers of the lower respiratory tract and pleura.
Researchers then began to wonder whether asbestos was
responsible for other cancers as well.
A 26 year mortality study by Elmes and Simpson (1971),
of Belfast insulation workers was conducted to determine
other possible cancers or causes of death associated with
asbestos.
One hundred and seventy men were followed from
1940 to 1966.
In this time span 37 deaths (21 percent)
•
~----
Table 1. Expected* and observed deaths among 17,800 asbestos insulation
workers in the United States, January 1, 1967-December 31, 1971
Distribution by duration from onset of exposure
Total
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20 years and more
Expected
Observed
Expected
Observed
Expected
Observed
Total deaths
805.63
1,092
178.94
211
626.69
881
Cancer: all sites
144.09
459
26.31
51
117.78
408
44.42
213
7.03
22
37.39
191
Pleural mesothelioma
**
26
**
2
**
24
Peritoneal mesothelioma
**
51
**
3
**
48
6.62
16
0.97
1
5.65
15
17.51
26
2.51
3
15.00
23
3.21
13
0.44
1
2.77
12
72.33
114
15.36
19
56.97
95
**
78
**
5
**
73
661.54
555
152.63
155
508.91
400
Lung cancer
Cancer of stomach
Cancer of colon, rectum
Cancer of esophagus
All other cancers
Asbestosis
I
Less than 20 years
All other causes
Number of men
Person-years of observation
17,800
86,300
12,681
62,673
5,119
23,627
*Expected deaths are based upon age specific death rate data of the U.S. National Office of Vital Statistics. Rates for 1968-1971 were extrapolated from
rates for 1961-1967.
**U.S. death rates not available, but these are rare causes of death in the general population.
Source: Selikoff and Hammond, International Agency for Research on Cancer, Lyon, France, October 4, 1972
(unpublished data distributed at the AIHA Technical Symposium Los Angeles, Calif.)
1.0
10
were expected.
The number
pf deaths which actually
occurred was 98 (57 percent).
The observed deaths exceeded
the expected deaths especially from 1955 onward, where a
high mortality was due to cancer of the lung.
Cancer of
the stomach, rectum and colon were observed, as well as
other non-respiratory system related cancers.
Ratios of
observed deaths over expected deaths (obs/exp) for all
causes was 2.6; for all cancers, 3.9; and for cancers of
the lower respiratory tract and pleura, 17.6.
Having established a relationship between asbestos
and cancers of all types, researchers then began to speculate about the relationship between cigarette smoking
(statistically proven to be a carcinogenic factor) and
asbestos exposure.
Selikoff and Hammond (1972), in their study of U.S.
and Canadian asbestos insulation workers, compared the
occurrence of deaths and cancers between smoking and nonsmoking asbestos workers.
Their data are shown in Table 2.
Of the 77 deaths resulting from mesotheliomas, 46 deaths
were observed in the smokers, 11 deaths in the non-smokers
and 20 deaths in men whose smoking habits were not known.
The figures for asbestosis and other cancers are similar.
Also interesting, is the fact that lung cancer was not
significant in non-smoking asbestos workers.
In another study, Selikoff and Hammond (1972) studied
the causes of death among 370 New York and New Jersey
·asbestos insulation workers.
!~~~-----~----··-----·
The data are presented in
---·-"------·--------·---·
TABLE 2. EXPECTED AND OBSERVED DEATHS AMONG 17,800 U.S. AND CANADA
ASBESTOS INSULATION WORKERS, JAN. 1, 1967 -DEC. 31, 1971*
No history
of cigarette
smoking**
Total
History
of cigarette
smoking
Smoking habits
not known
Number of men Jan. 1, 1967
17,800
2,066
9,590
6,144
Person-years of observation
86,300
10,163
46,615
29,522
Expected
deaths
Cancer all sites
Observed
deaths
----
Expected
deaths
----
Observed
deaths
---
Expected
deaths
----
Observed
_deaths
Expected
deaths
Observed
deaths
----
144.09
459
19.92
33
79.58
265
44.59
161
44.42
213
5.98
2
25.09
134
***
26
***
2
***
17
13.35
***
77
Pleural mesothelioma
Peritoneal mesothelioma
***
51
***
9
***
29
***
13
Lung cancer
7
6.62
16
0.95
1
3.60
8
2.07
7
17.51
26
2.52
4
9.53
14
5.46
8
3.21
13
0.44
0
1.80
7
0.97
6
***
78
*'"'*
4
***
45
***
29
All other causes
661.54
555
92.67
36
356.67
286
212.20
233
Total deaths
805.63
1,092
112.59
73
436.25
596
256.79
423
Cancer of stomach
Cancer of colon, rectum
Cancer of esophagus
Asbestosis
*Expected deaths based upon age specific U.S. mortality rates for white males, disregarding smol<ing. Lung cancer estimates based upon U.S. rates for cancer of
lung, pleura, bronchus and trachea, categories 162 and 163.
**Included 609 men who smoked pipes or cigars.
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***United States data not available, but these are rare causes of death in the general population.
Source: Selikoff and Hannond, International Agency for Research on Cancer, lyon, France, October 4, 1972
(unpublished data distributed at the AIHA Technical Symposium Los Angeles, California)
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Table 3.
Similar to the previous study, excessive deaths
from mesotheliomas, asbestosis and other cancers occurred.
The ratio of observed deaths from all cancers in those
workers who did not smoke over the expected deaths is 3.15.
Data from these studies clearly point to a close association between asbestos and all types of cancers.
Addi-
tionally, a synergistic effect between smoking and asbestos
exposure appears to exist.
Because cancers caused by asbestos and cigarette smoking are suspected of following a "20 year rule", studies
must be run for long periods of time.
Epidemiological
study groups are being followed closely in order to better
define the effects of exposure to asbestos and the amount
of time required for these effects to manifest themselves.
It is likely that the health effects from recent
widespread use of asbestos will not be evidenced until
after the year 1980.
Toxicology
Perhaps the least known and most evasive characteristic of disease associated with asbestos exposure is where
and how the toxic effects occur.
It has never been suffi-
ciently shown how much exposure is required in terms of
concentration, time, pattern, form of asbestos fiber and
what the characteristics are of those persons who are
particularly susceptible to these effects.
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TABLE 3. EXPECTED** AND OBSERVED DEATHS AMONG 370 NEW YORK
NEW JERSEY ASBESTOS INSULATION WORKERS, JAN.1, 1963-DEC. 31,1971
Number of men Jan. 1, 1963
Person years of observation
87
283
608
1,912
Expected
deaths
4.75
15
10.99
79
1.26
***
1
-
3.31
***
41
5
20
***
7
***
13
---15.74
94
4.57
***
42
Pleural mesothelioma
Peritoneal mesothelioma
***
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Cancer all sites
Observed
deaths
Observed
deaths
Expected
deaths
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370
2,520
dea~
Expected
deaths
I
History of
cigarette smoking
No history of
cigarette smoking*
Total
Observed
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Lung cancer
5
Cancer of stomach
0.94
6
0.30
2
0.64
4
Cancer of colon, rectum
2.15
6
0.69
2
1.46
4
Cancer of esophagus
0.37
-
0.11
-
0.26
***
21
***
5
***
16
All other causes
69.22
53
27.03
15
46.94
38
Total deaths
84.96
168
27.03
35
57.93
133
Asbestosis
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*Included 39 men who smoked pipe or cigars.
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**Expected deaths based upon age specific U.S. mortality for white males, disregarding smoking habits. Lung cancer estimates based upon U.S. rates for
cancer of lung, pleura, bronchus and trachea, categories 162 and 163.
***United States data not available, but these are rare causes of death in the general population.
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Source: Selikoff and Hammond, International Agency for Research on Cancer, Lyon, France, October 4, 1972
(unpublished data distributed at the AIHA Technical Symposium Los Angeles, California)
I ------
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14
To identify the factors associated with asbestos toxicity, studies of the action of asbestos on living tissues
have been conducted utilizing laboratory animals.
Experimental animal studies have been conducted since
the early reports of asbestos related diseases became
known.
Data from these animal studies, however, are not
adequate to compare and extrapolate to real exposures
experienced by human beings.
The major difficulty being
the large doses of fibers which must be implanted or
injected into the test animals to illicit a toxic response
within a reasonable time frame.
This method of experimental study loses credibility
with regard to similar responses occuring from smaller more
"routine" exposures in human beings.
A classic example of this fact was the production of
diffuse pulmonary fibrosis in guinea pigs by Gardner and
Cummings and by Vorwald, et al.
These experimenters were
able to produce pulmonary fibrosis, only after administering large experimental doses of from 1,400 to 5,000 fibers
per cubic centimeter (NIOSH Criteria Document, 1972).
Experimental studies with animals have been a useful
information source.
Much of the data gathered from these
experiments has been helpful in determining factors which
influence the toxicity of asbestos fibers, once they are
deposited within living tissues.
In the early studies of asbestos toxicity it was sug:gested that the longer fibers were more toxic than the
..._,.
___
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·--~----:
15
shorter-ones~-----Ti1Is--was--a-EtributecCEo--a-s1isp-ecte-cCa-ssocTa=·--­
tion between the immobility of the longer fibers and their
contact with the same cells for extended periods of time
(Vorwald, Durkan and Pratt, 1951).
Timbrell (1965), supported this viewpoint after con·ducting inhalation experiments on live rats and the hollow
casts (plaster copy) of a pig's lung.
His experiments
showed that aerodynamically, small straight fibers were
best able to reach the lower pulmonary air spaces as compared to longer straight fibers and the curly fibers of
chrysotile.
However, due to the deposition characteristics
and toxicological actions, it appeared that the longer
fibers most often produced fibrosis and were, therefore,
more toxic.
Asbestos bodies have been found to be important in the
diagnosis of asbestos diseases.
Asbestos bodies occur in
various shapes and are found in the lung, sputum and feces.
These bodies appear brownish or black in color and are
often dumbell in shape.
This shape arises from the activ-
ity of the macrophages (white blood cells) in trying to
engulf the asbestos fiber.
An iron-containing protein gel
coats the fiber and is twice as thick at the ends of the
fibers, accounting for the dumbell-like shape.
The finding
of asbestos bodies in sputum or lung biopsy proves that an
exposure to asbestos has occurred (Hamilton and Hardy,
·1974).
16
F. Pooley (1972), extracted asbestos bodies from the
lungs of human beings and examined them under an electron
microscope.
He was able to prove from these examinations
that asbestos bodies were rarely formed around fibers less
than 10 microns in length and nearly always on straight
fibers.
Asbestos bogy formation around chrysotile asbestos
was very infrequent.
Other innoculation and inhalation experiments show
that various types of asbestos fibers, man-made monofilamentous fibers and chemical impurities in asbestos
fibers are all capable of producing toxic reactions in
experimental animals.
Common factors among these experiments lead one to
believe that asbestos fibers give rise to a toxic response
because they are long stiff fibers which mechanically irritate living tissues, particularly tpose of the lung.
The
theory that the effects of asbestos are chemical in nature
has at least been partially disproved by inhalation experiments utilizing finely ground (less than 2 microns in
length) asbestos.
Inhalation experiments which exposed
animals to high concentrations of this finely ground dust
showed no fibrogenic response occurred among any of the
test animals.
In contrast, an inhalation experiment
involving the same asbestos in the usual long fiber form
and one third the concentration of the finely ground dust
experiment, produced marked fibrosis after two years of
exposure (Johnstone and Miller, 1960).
17
Strong evidence also supports the view that the first
few years of exposure to asbestos fibers are an important
determinant as to the final outcome or occurrence of disease.
Isolated, but verified cases exist where as little
as a single month of exposure to airborne asbestos dust was
followed by fatal asbestosis 30 years later, with the
entire intervening period one of good health and no further
exposure to asbestos (Fleming, d'Alonzo and Zapp, 1960).
Determination of Disease
Determining the occurrence of a disease thought to
have been caused by exposure to asbestos is a very difficult task.
The decision, usually left to a medical doctor,
can only be made after an extensive evaluation of the
persons medical history, employment history, environmental
exposure, diagnostic laboratory tests and physical examinations are completed.
It is believed that often in the past many cases of
asbestosis and asbestos related cancers were not identified
as such, because the attending physician was not aware of
an occupational association with asbestos since little data
on the subject had been compiled.
Once it became apparent that definite health effects
were occurring from asbestos exposure, employes were monitored with periodic medical examinations.
18
The results of these examinations have led to a valuable index of information describing early signs and symptoms of asbestos caused diseases.
Usually, the average monitoring program consists of a
routine (yearly) chest x-ray and pulmonary function tests,
'
'
~articularly
lung vital capacity.
Irregularities in these
test results are usually indicative of problems or disease
associated with the pulmonary tract and lungs.
Unfortu-
nately, by the time radiological and vital capacity changes
are·detected in an asbestos worker, pneumoconiotic morphological changes are advanced to the point where no means of
medical prevention is effective.
Much effort has been expended to formulate early
detection methods for discovering the preliminary stages of
asbestos related illnesses.
For instance, it has been
shown that before obvious changes in the x-ray pattern of
a person exposed to asbestos occurs, the lung presents
fibrotic changes along the lymphatic system in the interlobular septa and in the peribronchial and perivascular
areas (Chiappino and Briatico-Vangosa, 1973) .
Progressive
fibrosis of the lung tissue may occur as early as 3-6 years
after initial exposure to asbestos.
Little or no detect-
able lung fibrosis need be associated with benign pleural
changes or mesothelioma after asbestos dust exposure.
Microtraumas of the alveolar walls, induced by asbestos fibers, are manifested by fine basal rales (bubbling
;sounds) at auscultation and the presence of siderocytes and
-----------~-----------~-----'
19
asbestos fibers in the sputum.
The appearance of these
substances in the sputum of an individual is a definite
sign of asbestotic alveolitis (Chiappino and BriaticoVangosa, 1973) .
Other non-specific findings are also often helpful in
determining the early stages of asbestos related diseases.
One of the first changes from the so-called "normal
lung" is when hilar shadows become prominant.
These shad-
ows may be due to accumulating dust particles within the
lymphatic system of the hilum and are the same for all
types of dusts capable of producing the pneumonoconiosises.
However, they may also merely be evidence of the aging process, since they occur in older individuals who have not
been exposed to such dusts.
These shadows become exagger-
ated with each advancing decade of life.
Such shadows may
become evident earlier in life as a result of chronic respiratory infections (Johnstone and Miller, 1960).
The Asbestos Health Standard
Concern for the health and safety of the working man
has steadily grown since men first began to work.
As new
materials and methods were developed, workers were subjected to increasing risks to their health and well-being.
Labor laws were passed and many attempts were made to limit
these risks.
Dreessen proposed the first standard aimed at control-
i
:ling exposures to asbestos (Lynch and Ayer, 1968). His
i
-------~----____,j
·------------·--------·--
20
observations brought about the first tentative limit of
5 million particles per cubic foot (mppcf) for airborne
concentrations of asbestos dust.
This limit then stood as
the accepted health standard until 1970.
In 1970 congress passed the Williams-Steiger Act.
This law, better known as the Occupational Safety and
Health Act (OSHA), was enacted to require employers to
provide a safe and healthful workplace for the working
people of the United States.
An enforcement agency, also known as OSHA, was set up
within the Department of Labor.
The OSHA agency is respon-
sible for adopting and enforcing detailed safety and health
standards.
To ensure that adequate health standards are adopted
by the OSHA agency, the National Institute for Occupational Safety and Health (NIOSH), was organized within the
Department of Health, Education and Welfare.
NIOSH
researches known or potential health hazards and makes
appropriate recommendations to the OSHA agency for controlling exposure to these hazards.
One such recommendation was the criteria for a recommended standard ... "Occupational Exposure to Asbestos" of
1972.
In this document, NIOSH presented extensive research·
dealing with past and present environmental and epidemiological data.
A detailed analysis of the various methods
.used to measure and quantify asbestos worker exposures was
also conducted.
21
- ---·rrh.e·--:r:ec:ornm:eiiCfe<I-standard:_o_:f_s_···riEers~--I·c;n.·g
ertilan-
·-------~
5 micrometers (microns) in length, per cubic centimeter of
.air was derived from available data concerning the factors
associated with disease production and available sampling
methods.
Consideration of fiber size is an important part of
the standard and is consistent with the data previously
presented in this paper.
The allowable level of 5 fibers per cubic centimeter
as specified in the recommended standard and the legal
standard of July 7, 1972, appears to be a rather subjective
extrapolation from several dissimilar studies and analyses.
Nevertheless, some level of exposure had to be associated
with causation of disease and the 5 fibers per cubic centimeter was considered to be acceptable in line with available epidemiological evidence.
Because the effectiveness
of the standard is unknown with relation to disease production, the permissible level of exposure to asbestos dust
will be mandatorily lowered to 2 fibers,
longer than
5 micrometers in length, per cubic centimeter of air, on
July 1, 1976.
Many observers feel that allowable exposure to airborne asbestos dust should be eliminated entirely because
of the known and proven toxic effects of asbestos.
No
current effort to examine the practicality of this approach
iis being undertaken by OSHA or NIOSH.
t--~---~----~--------
CHAPTER 3
PRELIMINARY SURVEY
Purpose
Industrial hygiene engineering begins with the identification of an industrial operation which is potentially
hazardous to employes health and well-being.
Once dis-
covered, the hazardous operation is subject to a comprehensive review and analysis.
A preliminary survey is
conducted to identify, exactly, those agents and operations
which are potential risks to an employes health.
Identifi-
cation of the hazardous agent is the most important phase
of any industrial hygiene analysis.
Once identified, the
hazardous agent must be traced along the process flow and
evaluated for its health risks at each new phase.
A preliminary review of employes health histories may
also be helpful in revealing if and where an actual health
risk·is occurring.
Similiar distincitive changes in
several employes health become significant, particularly
among small groups.
Utilizing this preliminary data, the industrial
hygienist can initiate a comprehensive sampling and evaluation plan, the final outcome of which will be determined
by all data gathered including that gained in the preliminary survey.
- - - --·--··-------------------·-·------22
23
Phenolic Asbestos
Phenolic asbestos is a proprietary asbestos product
which is used primarily as an erosion resistant and high
temperature thermal insulating material.
Varying types of phenolic asbestos are manufactured
by the Reinforced Plastics Department of the Raybestos
Manhatten Company of Manheim, Pennsylvania.
Raybestos
Manhatten (R/M) style 41-RPD Pyrotex felt tape was found
to be exclusively used in all operations within the scope
of this study.
R/M style 41-RPD is manufactured from long spinning
grade chrysotile asbestos fibers carded into American
Society for Testing and Materials (ASTM) grade AAAA
(99-100 percent pure asbestos) felt.
This asbestos felt
is then impregnated with a special heat resistant phenolic
resin, "B" staged (intermediate stage in the cure of a
thermosetting resin) and trimmed to a specified width for
high and low pressure laminating and lay-up molding
processes.
Impurities in R/M style 41-RPD are those inherently
found in all chrysotile asbestos such as brucite, magnesium
carbonate and magnitite.
R/M style 41-RPD has the lowest
amount of magnitite possible (Raybestos Manhatten, 1963).
Identification of Potential Risk Areas
The preliminary survey revealed that phenolic asbestos,
24
foi~
- a--IIquld.____:fuer--ro-c-ket._motor--a-n'd--as--an~·aEiatfon-re s-Is-tar:t·
heat shield for associated equipment in the rocket motor
system.
Before the phenolic asbestos is incorporated in the
rocket motor system, it passes through several fabrication
'and machining phases.
A flow chart appears in Figure 1
which depicts these major phases and the number of employes
involved in each phase (circled).
Upon receipt, the phenolic asbestos tape is enclosed
in plastic bags.
The phenolic resin is uncured, which
makes the phenolic asbestos tape "tacky."
It appeared
unlikely that airborne asbestos fibers could be generated
from the use of the uncured tape.
Since the phenolic
asbestos tape is handled in this form in board lay-up, tape
wrapping, hydroclave cure and compression molding, no risk
to the health of employes involved with these activities
is suspected.
Once fabricated and cured, the phenolic asbestos is
machined into the required part configuration.
is done with a lathe, mill and band saw.
Machining
Observation of
these tasks revealed that lathe and mill operations are
done with the benefit of local exhaust ventilation while
the band saw operation is not.
Several operations
appeared to be dirty and dusty and were suspected of
exceeding the legal airborne asbestos dust level of
_5 fibers per cubic centimeter.
----------------------·----·
r--·------···
PRE-FABRICATED BOARDS
II
"-----.------' 0
1
- -- --
®
@
@
®
FIGURE 1. PHENOLIC ASBESTOS MATERIAL FLOW CHART
0
Circles indicate number of employes potentially exposed.
t0
ln
26
After machining, the phenolic asbestos part has a hard
smooth surface much like any other resin after curing.
Because the asbestos is "bound" within the phenolic resin,
it is not expected to present a health risk to employes
handling or delivering the part.
The phenolic asbestos part is often sawed, drilled,
filed or sanded by technicians before final installation
into the rocket motor system.
Sawing is done on a band
saw which is equipped with a local exhaust ventilation
system.
All other machining is done with small hand tools
outdoors under ambient conditions.
These operations,
particularly the band saw operation, appeared to be producing excessive levels of airborne asbestos dust.
Installed, the phenolic asbestos part remains in the
bound condition until the rocket motor system is fired.
The rocket motor exhaust subjects the phenolic asbestos to
temperatures up to 8,000 degrees Fahrenheit, oxidizing
rocket fuels and ablative particulates.
off" of the phenolic asbestos occurs.
Erosion and "burn
The asbestos is
carried off with the exhaust cloud into isolated remote
terrain.
Employes are not subjected to the exhaust cloud.
Residual asbestos may be present in the air, but because
the test area is outdoors and naturally ventilated, this
premise appears unlikely.
After being subjected to the
rocket motor exhaust, the phenolic asbestos surface is
:charred, but remains intact.
The asbestos is still bound
iin the remaining phenolic resin.
'----·
27
which is picked up by a refuse contractor who disposes of
the material in a sanitary land-fill.
Employe Medical Histories
A review of the medical histories of employes required
to handle phenolic asbestos was conducted to determine if
similar health effects were occurring among the group.
A
random sample of these brief medical histories is contained
in,Appendix 1.
Hazardous job physicals, which include a chest x-ray
and lung vital capacity test, have been conducted on many
of the exposed individuals for several years.
A statisti-
cally significant change in respiratory tract parameters
among individuals in the exposed group would serve as an
indictor that excessive exposures have occurred.
The data gathered from the medical histories of
employes although admittedly limited, revealed certain
similarities.
A reduction in lung vital capacity was
observed in many of the employes in the group.
Vital
capacity is a diagnostic test designed to measure elasticity of the lungs.
When vital capacity is reduced, it is
usually indicative of disease, illness or impairment
involving the respiratory system.
Chest x-rays revealed some changes, such as the
appearance of hilar calcifications, that could be linked
to asbestos exposure.
Due to limited information and
28
incomplete personal histories for employes in the group,
no creditable or statistically significant conclusions can
be drawn from this data.
The fact that asbestos-related diseases do not manifest themselves except after long periods of time, make the
chance for the appearance of clinical symptomology of
asbestos and cancer related diseases among the employes
very small.
All employes exposed to phenolic asbestos have
worked with it for 15 years or less and their previous
histories of exposure to asbestos are very limited and
most often unknown.
Employes with significant reductions in their vital
capacities were compared to see if a correlation with job
assignment existed.
In all but one instance, the employes
were machinists or technicians involved with fabrication
and machining of phenolic asbestos.
Results of the preliminary study indicate that chrysotile asbestos is the harmful agent in the work environment.
Preliminary review of the material, material flow and
medical histories indicate exposures to airborne concentrations of asbestos have occurred and may be continuing,
particularly in the fabrication and machining phases.
Determination of whether concentrations of asbestos fibers
in air, during certain process phases, exceed the perrnissible legal limits will be determined by sampling and
:analyzing the work environment.
MATERIALS AND METHODS
Instrumentation
Four battery-operated Mine Safety Appliances (MSA)
~odel
G Monitaire sampler pumps with pulsation dampeners,
were used to collect personal and area air samples around
the various phenolic asbestos operations.
The diaphram
pumps are manufactured and approved in accordance with the
requirements of 30 CFR (Code of Federal Regulations),
Part 74, March 11, 1973, which prescribes the recommended
flow rates and pulsation dampening characteristics of
diaphram pumps.
The Monitaire pump is lightweight and can be attached
to a workers belt with the aid of a clip.
The air flow
rate is adjustable between 1 and 10 liters per minute.
Approvals and specifications for the MSA Monitaire are
listed in Table 4.
TABLE 4.
MINE SAFETY APPLIANCES MONITAIRE SAMPLER
MODEL G APPROVALS AND SPECIFICATIONS
Approvals:
Factory Mutual (FM)
30 CFR, Part 74, 3/11/73
Bureau of Mines, No. 2F-2004
Specifications
Type:
Diaphram
Dimensions:
2-1/2 in. x 5 in. x 5 in.
Weight:
31 oz.
Battery:
6 volt; rechargeable
Battery Life:
8 hours continuous operation
Flow Rate:
1-10 liters per minute (lpm)
Recharging Time:
16 hours overnight charge rate
64 ll9_-q_fE._w_~-~~e~_g __g_l)a:r._g§.._ rate
---·---~
29
30
The Monitaire pump draws air into the inlet port as
the pulsating diaphram creates a vacuum on the inlet side
of the diaphram.
A two foot long piece of one-eighth inch
Tygon tubing, connects the inlet port of the pump to a
filter sampling head.
The sample is collected onto filter
paper similar to the action of a vacuum cleaner.
The flow
rate of the MSA Monitaire is calibrated with the aid of a
1 liter glass "bubble" buret.
The buret is a recognized
primary standard for the calibration of small air sampling
pumps.
The recommended flow rate for the Monitaire, when
used for asbestos sampling, is between 1.7 liters/minute and
2.5 liters/minute.
The sampling head which connects to the end of the
Tygon tubing coming from the sampling pump, consists of a
3 part plastic holder, a filter pad and a 37 millimeter
Millipore type AA cellulose-ester-membrane filter with a
0.8 micron pore size.
The proximal half of the sampling head has a small
opening to which the tygon tubing connects with the use of
an adapter.
The filter pad, which supports the fragile
filter and also aids in controlling air flow through the
filter, is placed into the proximal portion of the sampling
head.
The filter is then placed on top of the filter pad.
The middle retaining section of the sample head is then
inserted into the proximal section to hold the filter and
pad secure.
.~
cellulose band is placed around the proximal
and middle sections to hold them together as well as make
----------··-----'
31
put into place until sampling begins, at which time it is
removed for
11
0pen face 11 sampling.
Other equipment necessary for sampling was a stopwatch
for timing sample durations, an adjustable waist belt for
attaching the pump to the subject, alligator clips for
attaching the Tygon tubing and sampling head to the subject
and a label maker for identification of the sampling heads.
To analyze the environmental air samples, a Zeiss
microscope equipped with phase contrast, Koehler illumination and Polaroid camera attachment was used.
Total magni-
fication of the samples was 625 times (x), due to the use
of 12.5 x occulars, a 1.25 x optivar and a 40 x
(0.65
numerical aperture) phase-contrast objective.
An eyepiece porton reticle was necessary for counting
and sizing the asbestos fibers.
A stage micrometer was
required for calibration of the reticle.
To mount the samples, a mounting solution consisting
of dimethyl pthalate and diethyl oxalate (combined in a one
to one ratio by volume) mixed with five hundredths of a
gram of the Millipore AA cellulose-ester filter material
was used.
Additional equipment necessary for the analysis of the
environmental samples was glass microscope slides for
mounting the samples, glass cover slips for covering the
samples on the slide, scalpel and tweezers for cutting and
·removing the filter paper from the sample head, Wheaton
32
balsam bottle for storage of the
mounting solution and a
.
/
pencil with an eraser for "setting" the sample.
Sampling Strategy
An integral part of industrial hygiene programs is the
periodic monitoring of the atmosphere in the work environment.
Airborne concentrations of harmful air contaminants
which may be presenting a risk to the health of an employe,
are readily identified using this technique.
Atmospheric
sampling is conducted to evaluate new processes or materials, employe complaints, effectiveness of engineering
controls and most often, to determine compliance with occupational safety and health regulations.
Generally, air
sampling is done in such a manner as to simulate the exposures an employe is experiencing.
This includes all opera-
tions where a potential airborne concentration of hazardous
material may exist.
Analysis of the air is not an easy task.
Although it
appears to be simple in nature, air sampling is complex
and often misunderstood by inadequately trained individuals.
Careful attention must be given to items such as
equipment operation, calibration and selection of sampling
locations, in order to obtain air samples representative
of the work environment.
Careful documentation of ambient conditions existing
at the time of sampling, such as temperature, humidity,
local exhaust controls and process conditions, is crucial
-------------·----·--·-··---
33
data which is utilized in the final interpretation of the
air sampling results.
Locations where air sampling should be conducted are
determined by where the employe is stationed during the
work cycle.
"Operator breathing zone"
(OBZ), samples are
the most effective type for quantifying the levels of air
contaminants to which a worker is exposed.
These samples
are collected near the face of the employe and theoretically
"breath in" the same contaminants as the employe.
Adjacent area samples are sometimes collected to
identify levels of contamination neighboring equipment and
other surrounding employes may be experiencing.
Air sampling duration may be from a few seconds to an
entire 8 hour work day.
Samples collected for short peri-
ods of time, usually less than 5 minutes 7 are called "grab"
samples.
The atmospheric concentration (of a contaminant)
is assumed to be constant throughout a grab sample because
of the short time period.
Several grab samples are fre-
quently collected in a series to approximately define total
exposure.
Samples collected for longer periods of time (15 minutes to 8 hours), are known as "long term" samples.
These
samples are collected over long periods of time so that
variations in the industrial cycle are averaged.
Long term
samples are preferred over grab samples in atmospheric
'monitoring, but they often mask peak concentrations which
·may occur in an industrial cycle.
'
~--~·-·---~-·-·-~-,-----
Grab samples are useful
34
@
in locating these peaks within a cycle (Olishifski and
McElroy, 1971).
In determining the length of time a sample is collected, it is important to note that the method of analysis
for determining the sample concentration is the most important factor regulating the sampling duration.
This is
particularly true for asbestos air sampling time durations,
because the reliability of the analytical method is sensitive to the amount of material collected.
Leidel and Busch (1975), stated that, "an increase in
sampling time lowers the variability of the data and
reduces the width of the confidence limits on the mean,
thereby yielding 'better' answers."
The foregoing state-
ment is almost completely untrue for short term grab
samples, where the primary consideration in selecting short
sampling times is the analytical method.
Each analytical
method requires that a minimum amount of material be collected.
Any increase in sampling time past the minimum
time required to collect an adequate amount of material is
therefore, unnecessary and unproductive (Leidel, 1974).
The number of samples which should be collected
relates to the reliability of the estimated air concentration and employe exposure, irrespective of the sample durations.
This is true for 8-hour time-weighted concentra-
tions, operational exposures and area contamination.
The number of samples which should be collected is
'dependent upon the reliability of the sampling method.
-------·-·------------
•
35
In air
monitori~g,
it is not uncommon for air sample con- 1
centrations from similarly collected samples to differ by
a factor of 5 or more.
Good industrial hygiene practice
provides that a minimum of 3 air samples be collected and
analyzed to ensure that the variability among samples is
not excessive and that a "trend" among the samples is
established.
Once a trend is shown to exist among samples,
it is desirable to collect only the minimum number of
samples necessary to make a valid prediction of the airborne concentrations.
Leidel and Busch (1975), of NIOSH, have related the
minimum number of samples required to narrow the confidence
interval to the time duration of the sample.
They have,
based on statistical considerations, concluded that the
optimum number of long term (8-hour) samples necessary to
predict a valid concentration is two.
For short term grab sample durations the optimum number of air samples which must be collected to make a valid
determination of the airborne concentration has been shown
to be a minimum of 2 and a maximum of 7 samples (Leidel and
Busch, 1975).
Environmental Sampling
Atmospheric samples were collected for specific phenolie asbestos operations as identified in the preliminary
survey.
These operations were those suspected of having
!.-~·-------·-
--------------·--------------------------~
36
airborne asbestos dust concentrations in excess of allowable levels.
Before going out to collect air samples, the personal
sampling pump batteries were fully charged prior to each
use and the air flow rate of each pump was calibrated
utilizing the bubble buret.
Calibration was conducted
with a sampling head "in line" in the system to provide a
typical resistance to flow.
Personal samplers were placed on employes assigned
to perform the asbestos operations.
Sample heads were con-
nected to the pump line and attached to the worker's lapel
or collar.
Two sample heads were handled in the same
manner as all the others with the exception of never having
the lids removed or being used for sampling.
These sample
heads served as blanks for the analytical procedure.
While
attaching the sampling equipment, a short explanation of
the sampling method and directions were given to the
employe.
The covers to the sample heads were removed and the
personal sampling pumps turned on.
The time and all other
pertinent data were recorded on an asbestos sampling ticket.
A sample of one such asbestos sampling ticket is shown in
Figure 2.
While the samples were being collected, careful observation and notation of the work cycle and employe movements
were made in order to identify unique work habits or possi:ble contributing sources of interference.
\.......,_~-·-----·--------------~---------------------~----~--~----·_....;
37
Field Monitor No.
Instrument No.
Blank No.
Date
Flow Rate
Calibration
(Date & Flow Rate)
Time On
Time Off
Begin Flow
End Flow
Total Volume Sampled
Employe
Badge No.
Classification
Total Time
Area of Sample:
Description of Operation:
Description of controls/protective equipment in use (check)
Respirator
Exhaust Ventilation
Wet Methods
Other
Engineer
FIGURE 2.
ASBESTOS SAMPLING TICKET
38
When the operation was completed the pumps were turned
off and the covers replaced on the sample heads.
The sample
heads were then removed from the sampling line and placed
in a cushioned sample box.
Sampling pumps were removed and
placed in plastic bags and sample tickets were completed
and placed with the
sampl~s.
The samples were then placed in a well protected area
in the industrial hygiene laboratory while waiting to be
analyzed.
Sampling pumps were removed from the plastic
bags, decontaminated and returned to their charging and
storage area in the laboratory.
Because of the nature of phenolic asbestos use, intermittent short term operations were the general case.
In
order to obtain air samples representative of routine
employe exposures, samples were collected in the location,
for the duration and on the employe for which they were
normally occurring.
The band sawing operation air samples
at the Aerothermochemical (ATC) laboratory were an exception.
Initial samples of this sawing operation, which were
run for actual task times, were so heavily loaded that no
valid microscopic analysis could be performed.
Accordingly,
the sampling durations for the band sawing operation were
reduced to very short time durations so that a reasonable
estimation of the airborne concentration could be made.
i
----------·----·~-----~-~-~----·----
39
Sample Preparation
Once the air samples were collected, it was necessary
to prepare them for microscopic analysis.
Extraction of
the filter from the sample head and mounting it on a microscope slide was one of the most important and difficult
operations performed.
Great care had to be exercised, so
as not to disturb or alter the arrangement of the impacted
asbestos dust on the filter paper.
Sampling heads were gathered from the storage area
and readied for analysis when a suitable number of samples
existed. · Because of the cleanliness requirement, mounting
medium shelf life and availability of the microscope, it
was advantageous to prepare and analyze as many samples as
possible at one time.
To mount a sample, the lid of the sampling head was
removed.
Using a scalpel with a number 10 blade, a
triangular-shaped piece of filter paper (about one-eighth
of the total filter area) was carefully cut from the filter
and the cover put back on the sampling head.
A drop of the mounting solution was placed on a clean
microscope slide using a small glass rod.
The solution was
then smeared into a triangular shape slightly larger than
the wedge-shaped filter paper previously cut.
The cover of the sampling head was removed and the
filter paper wedge carefully lifted out by the outer
.rounded edge with a pair of tweezers.
The filter paper
:wedge was aligned with the mounting solution wedge and
_____ •..1
40
p '
carefully lowered onto the mounting solution with the
asbestos side up.
A cover slip was gently lowered onto the
filter wedge and mounting solution.
To "set" the sample,
the eraser end of a pencil was used to gently tap the cover
slip down until it made contact with the mounting solution.
The slide was then labeled with the number from the
sample ticket for identification.
An asbestos count record
sheet was numbered with the same identification number as
the sample head in preparation for the microscopic analysis.
A sample of the asbestos count record sheet appears
in Figure 3.
After approximately 30 minutes the membrane filter
wedge became transparent and the slide was ready to be
counted.
Asbestos slides were counted within 5 days after
their preparation because crystals, which look similar to
asbestos are known to develop in the mounting solution
after 5 days and therefore, could have led to false fiber
counts (Bayer and Zumwalde, 1973).
Microscopic Analysis
The recommended counting method for the slide mounted
asbestos samples consists of conducting fiber counts under
phase-contrast microscopy at 400-450 power (x)
1973).
(NIOSH,
This magnification range was chosen by NIOSH as
being universally available and the most economical in
cost.
The microscope used for this study, as explained
earlier, was equipped to supply a magnification of 625 x.
41
Sample ticket No. _ _ _ _ Operation _________ Date _ _ _ _ _ _ __
Flow ______ Time ______ Volume ______ Blank count _ _ __
Initials _ _ _ _ _ _ _ Field area ________ Average count_____ _ __
Comments:
5
10
15
I
20
Concentration = ...___ _ _ _.l-..J(=8=5=5._) = fibers/cubic centimeter
) (
(1000)
FIGURE 3. ASBESTOS COUNT RECORD SHEET
---------
42
scope, a portbn reticle was used in conjunction with the
right eyepiece of the microscope.
The porton reticle con-
sists of a rectangular section which is used to define the
counting area of the microscope field and nine sizing
'circles for determining fiber lengths.
The porton reticle was calibrated with a stage micrometer in accordance with recommended methods.
A reticle
calibration worksheet was used for this purpose and appears ·
in Figure 4.
Microscope
Eye Piece
X
Objective
X
Viewing Power
X
Date
Calibrated by
1.
200L (entire length) =
mm
2.
lOOL
=
mm
3.
lOOL X lOOL
=
mm
4.
Calculate circles
Circle #1 = L X
Circle #2
=
L X
Circle #3 = L X
Circle #4 = L X
Circle #5
Circle #6
=
=
L X
L X
2
=
field area
1.414 =
2.000
2.828
=
=
4.000 =
5.657
=
8.000 =
Circle #7 = L X 11.314 =
Circle #8
Circle #9
FIGURE 4.
=
=
L X 16.000
L X 22.627
=
=
RETICLE CALIBRATION WORKSHEET
;
'·--~---·------------------------------·-~-------·-----"
43
was taken to see that the microscope was set up properly.
This included the light train (Koehler) , as well as the
alignment of the phase contrast annular rings.
A standard
checklist was followed to ensure that each time the microscope was set up, it was done so in the same manner and at
·the same settings.
Upon calibrating the porton reticle,
the size of the counting area was determined and the
5 micron diameter reference circle was calculated from a
standard formula.
The reticle calibration worksheets were
used to conveniently calculate these values.
The left and top sides of the counting area were
designated as the sides to be considered for counting purposes as specified in the NIOSH procedures for sizing and
counting asbestos.
In order for a fiber to be counted, it
was required that it be three times as long as it was wide
(a 3:1 aspect ratio) and that it was 5 microns or greater
in length.
Additionally, the fiber had to lie completely
in the designated counting area or cross the top or left
sides of the counting rectangle, with one end being in the
counting area.
Random field areas were obtained by moving the microscope stage slightly while not looking into the microscope.
Counting fields on the outlaying areas of the filter wedge
were disregarded and excluded from counting.
The number of
fibers observed in each field which met the counting crite- ·
!ria, was recorded on the asbestos count record sheet.
44
Polaroid photographs were taken of representative
field areas for each sample analyzed.
Figure 5 is an
enlargement of a typical photograph of a representative
field area as viewed under the phase contrast microscope.
The number of field areas to be counted for each
sample is recommended by NIOSH, to be 20 field areas or
100 fibers, whichever is last.
In no instance is it
recommended that more than 100 field areas be counted for
any one sample.
To maintain a consistant number of field
areas counted for each sample and to assure a reliable
average fiber count, 100 random field areas were observed
for each of the samples in this study.
Once the number of fibers per 100 fields was determined for each of the air samples collected, the concentration of asbestos fibers in the sampled air was determined
mathematically by the following equation:
C
=
(A.F.C.-B.A.F.C.) (Filter area)
(Field area) (volume) (1000)
=
concentration of asbestos in fibers per
where
c
cubic centimeter (cc)
A.F.C.
= average fiber count for one hundred field
areas
B.A.F.C.
=
average fiber count of blank background
control filter
Filter area
=
855 millimeters squared for a 37 millimeter diameter Millipore filter
------- · - - -
45
FIGURE 5.
REPRESENTATIVE MICROSCOPE FIELD AREA AT 1500 X
46
Field area
=
0.002 millimeters squared counting area
of the calibrated porton reticle
Volume
=
total volume of air sampled determined by
the pump flow rate times the sampling
time
1000
=
conversion factor to change liters to
milliliters
The concentration calculations for each of the air samples
was computed at the bottom of the asbestos record count
sheets (see Figure 3).
p '
CHAPTER 5
RESULTS
Concentration Levels
Air samples collected for this study are listed in
Table 5.
Each of the 30 samples v7as identified with a
sample number when collected.
These sample numbers were
used for identification of the sample throughout the
collection and analysis operations.
Calculated concentration levels for each of the air
samples are shown in Table 6.
The concentration level was
calculated from the formula discussed previously.
Concentrations which were less than the 5 fibers per
cubic centimeter (fibers/cc) were calculated for all the
tape wrapping, milling and lathe operations.
Concentra-
tions greater than 5 fibers/cc were calculated for the
drilling operations at the Capistrano Test Site and at all
of the sawing operations (with the exception of the 3 area
samples collected at the ATC Laboratory).
A comparison of the air sample concentrations with the
legally allowable concentration of asbestos fibers in air,
show that all operations sampled, with the exception of the
ATC sawing samples, were v:i thin the allowable
11
ceiling
limit" set by OSHA (maximum concentration of 10 fibers/cc
never to be exceeded) .
47
r-····-·-····--
!'
TABLE 5. PHENOLIC ASBESTOS ATMOSPHERIC MEASUREMENTS
I
i
II
I
I
i
i
I
Sample Duration
Sample No.
Sample Location
Operation
Minutes
Liters Sampled
1
ATC Laboratory
Sawing
4.2
7.6
2
ATC Laboratory
Milling
226
434
3
ATC Laboratory
Milling
101
181.8
4
Building Two
Tape Wrapping
133
239.4
5
ATC Laboratory
Milling
142
255.6
6
ATC Laboratory
Sawing
4
6
7
A TC Laboratory
Milling
129
309.6
8
A TC Laboratory
Milling
80
155.2
9
10
ATC Laboratory
Milling
108
212.8
A TC Laboratory
Milling
70
137.9
11
ATC Laboratory
Milling
88
170.7
12
ATC Laboratory
Sawing
2.2
4.2
13
ATC Laboratory
Sawing
2.1
4
14
ATC Laboratory
Sawing
1.1
2.1
15
A TC Laboratory
Sawing
1
2
16
ATC Laboratory
Sawing
0.6
1.2
17
ATC Laboratory
Sawing
0.6
1.1
18
A TC Laboratory
Sawing
12.2
29.2
19.1
CAPO Test Site
Sawing
15.6
33.5
19.2
CAPO Test Site
Sawing
15.5
32.
19.3
CAPO Test Site
Drilling
8.6
18.4
19.4
CAPO Test Site
Drilling
8.5
17.3
I
19.5
CAPO Test Site
Drilling
8.8
18
I
21
CAPO Tt:st Site
Sawing
15.5
3.15
I
I
22
Building Two
Lathe
120
234
I
23
Building Two
Lathe
147
275
I
I
24
Building Two
Lathe
135
230.9
I
I
25
Building Two
Lathe
88
150.5
I
26
Building Two
Lathe
100
189
I
I
27
Building Two
Lathe
104
200.7
I
I
I
!
I
L.
ol::>
co
;--··
. -·-·-····-·--··.
TABLE 6. RESULTS OF PHENOLIC ASBESTOS ATMOSPHERIC MEASUREMENTS ANALYSIS
I
I
I
II
Concentration
Sample No.
Operation
Sample Duration
Liters Sampled
(fibers/cc
>5 mir:rons)
1
Sawing
4.2
7.6
2
Milling
226
434
3
Milling
101
181.8
0.49
4
5
Ta11e WrarJping
133
239.4
0.13
Milling
142
255.6
I
6
Sawing
4
6
7
Milling
129
309.6
0.54
i
8
Milling
80
155.2
0.77
9
Milling
108
212.8
0.64
I!
10
Milling
70
137.9
0.87
11
Milling
88
170.7
0.58
12
Sawing
2.2
4.2
165.9
13
Sawing
2.1
4
297.1
14
Sawing
1.1
2.1
443.8
15
Sawing
1
2
333.5
16
Sawing
0.6
1.2
215.5
l
I
I
I
Ii
i
i
l
104.1
0.41
0.35
101.2
17
Sawing
0.6
1.1
431.4
18
Sawing
12.2
29.2
24.3
19.1
Sawing
15.6
33.5
1.9
19.2
Sawing
15.5
32
6.9
19.3
Drilling
8.6
18.4
4.9
19.4
Drilling
8.5
17.3
5.2
19.5
Drilling
8.8
18
3.8
21
Sawing
15.5
31.5
4.2
22
Lathe
120
234
0.38
23
Lathe
147
275
0.22
24
Lathe
135
230.9
0.11
25
Lathe
88
150.5
0.48
26
Lathe
100
189
0.27
27
Lathe
104
200.7
0.30
~
1.0
50
The sawing sample concentrations exceeded the ceiling
limit by a factor from 10 to 40 times.
Time-weighted
averaging (8 hour) of these concentrations was prohibited
since the ceiling limit was exceeded.
CHAPTER 6
DISCUSSION
Exposures
Generally, the areas where airborne asbestos dust was
present (in concentrations in excess of the legally allowable level) were specific to two groups of employes.
These
groups were the machinists at the Newport Beach Facility
and the rocket test site technicians at the Capistrano Test
Site.
Both of these groups of employes are required to
machine and saw phenolic asbestos at irregular intervals.
Since the phenolic asbestos is used at the Capistrano
rocket test site, exposures to the rocket test site technicians are perhaps the greatest.
The machinists at the
Newport Beach facility are required to machine phenolic
asbestos about half as much time as the rocket test site
technicians.
Although it is very difficult to estimate what the
routine amount of exposure is per employe, it was indicated
from this study that the rocket test site technicians each
spend less than 150 hours per year machining asbestos.
The
machinists who are approved to work machining asbestos each
spend less than 75 hours per year machining asbestos.
The hours of exposure under normal conditions, are not
!spread
equally over each of the weeks of the year, but
,
I
iinstead occur in random blocks of time throughout the year.
51
52
--··
. . ···-
Each of these blocks of time was found to be 1 to 2 weeks
in length.
The rocket test site technicians spend anywhere
from 15 to 25 hours during this block of time machining
phenolic asbestos.
The machinists spend approximately
10 hours in support of the asbestos activities at the test
'site in this same time frame.
A closer examination of the machining tasks required
'of each group, shows that the rocket test site technicians
spend approximately 75 percent of their time involved in
machining activities that produce airborne asbestos dust
concentrations in excess of allowable health standard
limits.
On the other hand, the machinists spend less than
20 percent of their time involved in machining activities
that produce excessive dust concentrations.
Both groups, however, are required to saw the phenolic
asbestos boards.
The sawing operations at the ATC Labora-
tory and the rocket test site subject each of these groups
of employes to excessively high concentrations of airborne
asbestos dust.
A review of the brief medical histories (contained in
Appendix 1) for randomly selected members of each of these
two groups was conducted.
The number of machinists in the study group was four.
Of these 4 employes, 3 were shown to have lung changes
which could be associated with asbestos exposure.
One
employe, a smoker and longtime machinist of non-metallic
!
i
;materials recently died from cancer of the right lung.
L----~--------··-------~---~----------~~-·------------~----~-------------~-~;
53
Among the rocket test site technician study group of
9, 3 employes were found to have lung changes which could
possibly be associated with exposure to asbestos dust.
Of
the 5 who did not show changes, 2 were supervisory personnel who had only a casual exposure to asbestos dust.
Efforts to reduce employe exposures to asbestos dust
have been in effect for several years.
Local exhaust ven-
tilation controls for several of the machining phases are
responsible for
~he
low concentration levels found in the
milling and lathe operation samples.
The sawing operations
are not ventilated.
Rotation of employes assigned to machine asbestos has
also helped in limiting the exposure times of the rocket
site technicians and machinists.
Evaluation of Sampling and Analysis Methods
The sampling method for collecting airborne asbestos
dust is a straightforward, standardized industrial hygiene
method.
The use of the personal sampler for collecting
airborne contaminants is widely accepted by regulatory
agencies as being the best available method.
The MSA personal samplers used in this study proved
themselves to be very rugged and dependable pieces of
equipment.
The portability of the personal samplers and
their small size made the field and laboratory work quite
easy.
At no time were problems encountered with the
54
mechan.i.car or electrical systems, either-in the field or in
the laboratory.
Calibration of the sampling pumps was the most important phase of their use.
The bubble buret calibration of
the pumps was a simple task.
Of great importance, however,
was the care that had to be exercised in insuring that the
system was the same for each pump calibrated and that the
rotameters were set in the same manner for each of the
pumps.
A significant source of error can be introduced
into the sampling method if the calibration routine is not
conducted carefully.
Once the samplers were calibrated, the flow rate
reliability was found to be very good.
Several of the
sampling pumps were calibrated in the laboratory and then
subjected to the usual handling, bumps and on-off cycles
they would experience in the field.
A check of the flow
rates after this exercise showed that the flow rates were
within +2 percent of the original flow rates.
Sources of error, aside from the calibration cycle,
could be expected from faulty leaking connections,
insufficient battery recharging times and tampering with
the flow rate adjustment by the subject wearing the pump.
Care was taken to use the proper non-leaking connecting
devices, tape connections where appropriate, recharge
batteries a full 16 hour charging cycle before each use and
'to properly instruct the subject wearing the pump not to
I
!tamper with the control settings.
1.------~-----------·--------~·~-~----·--------------·--------·---------~·-----·-------------·
55
The membrane filter and three part plastic sampling
head were also found to be quite easy to work with.
The
sampling heads were purchased pre-assembled with the filter
paper and backing pad already installed into the sampling
head.
As previously mentioned, cellulose bands were placed
on the outside of the sampling heads to ensure an air tight
seal between the bottom and middle sections.
The Millipore filter is a very efficient collecting
medium for'asbestos dust.
All fibers, as well as dust
particles in excess of 0.1 micron, are retained on the
surface of the Millipore filter.
This is accomplished by
the 0.8 micron pore size which incorporates a tortuous (zig
zag) path.
Because the Millipore filters are often slightly contaminated with non-asbestos fibers, 2-4 percent of the
filters from each batch (lot) must be set aside and analyzed for background fiber counts.
The background samples
in this survey were found to contain 1-2 fibers per
100 fields counted, which presented no significant problem.
The major problem encountered with the use of the
membrane filter and the sampling head, was in the uniformity of the distribution of collected dust on the filter.
Because of certain factors
(many unknown or hypothetical) ,
the distribution of material on the filter could visually
be seen to be non-uniform.
samples collected.
This was true for most of the
More of the retained material appeared
to be present towards the center of the filter rather than
56
along
the- -ecfges-:-------rfflis"' ..:Eact--Ie·a:Cis- ·aiie
·t:c;--·s-uspe_c_t__ w:fi-et:l1er_____ ----
the collecting method is producing unbiased samples which
are truly representative of the work environment.
The Zeiss microscope used in this study was one of
much higher quality than was needed.
As mentioned pre-
viously, the magnification level of the microscope for
counting asbestos fibers was nearly 1-1/2 times the magnification level legally required.
Because of this fact,
more of the asbestos dust could be seen and, therefore,
probably led to a higher fiber count.
NIOSH (Cincinnati), was contacted and questioned as to
the "credibility" of fiber counts conducted under this
higher magnification.
Their response was that, "it is
quite acceptable and actually a 'more conservative'
approach than counting under a magnification of 400 x."
No significant problem was encountered in the use of
the microscope, other than the tedious task of aligning
and calibrating the equipment before each use.
Care was
taken to ensure that all fiber counts were made under as
nearly similar conditions as possible.
With well main-
tained equipment and the proper amount of exercised care,
the set-up and calibration of the microscope produces a
repeatable and reliable magnification.
The analytical method (fiber counting) was the most
difficult task to perform and control.
The subjectivity
of the individual conducting the fiber counts largely
57
fibers.
One of the early problems encountered in the counting
procedure was focusing on the proper plane (depth) of the
filter.
To maintain uniformity among the samples, a red
dot was placed on the filter with a ball point pen and this
dot was then utilized for initial focusing.
No more than
two complete revolutions of the fine adjustment knob was
made after this initial focus.
Another interesting fact associated with fiber counting, was that the first few fiber counts a person makes
(while still unfamiliar with the counting procedure) are
usually higher than those of an experienced counter.
To
eliminate as much error as possible in the counting of
fibers, an exchange of asbestos samples was made with an
industrial hygiene technician at the Long Beach Naval Shipyards in the early-learning stage.
Fiber counts compiled
by each observer were compared for uniformity.
Early fiber
counts made by this researcher were'often twice as high as
those of the experienced technician.
As the technique was
mastered, however, a close correlation of the two separate
fiber counts developed.
Rajhans and Bragg (1975) conducted a statistical study
of the variability of fiber counts among various observers.
They concluded that an experienced counter can consistantly
reproduce fiber counts to within 10 percent of each other
for similarly collected samples.
i
~--------·---~--~---~----~----~~------------------·-·-------------~-----·---···~------·····-~~---
58
Interferences with the counting procedure were numerous.
Dust produced in the machining process, as well as
naturally occurring airborne dust, was the most significant
interference encountered.
Because the dust collected on
the filter heavily outweighed the fibers collected, a
partial masking of the asbestos fibers occurred.
An
illustration of this point can be seen in Figure 6.
Another interference with the counting procedure was
large clumps of phenolic resin with asbestos fibers under,
around, or actually comprising part of the clump.
Figure 7
vividly shows this phenomenon and illustrates the problem
an observer has in determining how to count this fiber
clump.
Since no recommended method was available for hand-
ling this situation, it was arbitrarily decided to count
such clumps as three fibers when they were found within the
counting field area.
The clumps were more prevalent among
the sawing samples than in any other sample.
Because of the tendency for chrysotile asbestos to
aggregate and "splinter off", samples often contained
aggregate clumps of asbestos fibers.
These fibers, because
of the splintering effect of the fibers and fibrils,
appeared as multi-stranded long fibers.
Figure 8 displays
such an aggregate clump and helps identify the difficulty
in defining the diameter and length of any of these fibers.
Another interference source which must be taken into
account in all asbestos analyses, is the appearance of
non-asbestos fibers in the sample.
Figure 9 pictures a
59
FIGURE 6.
PHENOLIC RESIN DUST AND CHRYSOTILE ASBESTOS
DUST (1500 X)
- -
60
FIGURE 7.
P IIENOLIC RESIN AND AS BESTOS CLUMP
( 15 0 0 X)
,
61
FIGURE 8.
AGGREGATE CLUMP OF SP LINTERED ASBESTOS
FIBERS (1500 X)
62
FIGURE 9.
NON-ASBESTOS, BLUNT ENDED FIBER (1500 X)
63
non-asbestos fibei.
Th~se
fibers are easily
identifi~d
their blunt, flat ends and seemingly regular shapes.
by
CHAPTER 7
CONCLUSIONS AND RECOMMENDATIONS
This survey of the asbestos health problem and its
importance with relation to the phenolic asbestos operations
studied, produced some interesting data and identified some
of the problems encountered in the control of occupational
diseases.
Concentrations of asbestos fibers in air were quantitatively defined for each of the various phases of the phenolie asbestos process.
These concentrations, along with med-
ical history data, were used to identify employes who were
in a risk situation according to the recommended health
standard for asbestos.
The processes which produced high
levels of airborne asbestos fibers were also identified.
Although the membrane filter method of sampling and
analyzing asbestos dust in air is widely accepted, many
operational problems were encountered with the method.
These problems, particularly those in the analytical (counting) phase, were handled as objectively as possible and it
is doubtful that they would be responsible for biasing the
data results.
The sampling and analysis method proved to
be reasonably straightforward, reproducible and reliable.
In interpreting the results of the analyses, it is
important to keep in mind that the potential margin of error
which is possible within the method is high.
To provide a
95 percent confidence limit (2 standard deviations) for the
64
65
~
,,
sampling results, one must be aware that a potential error
margin of up to 30 percent exists.
Realizing that this large error margin is possible,
careful attention and consideration must be given to marginal situations before recommendations are made.
Asbestos dust has been shown to be a significant health
hazard to those occupationally exposed to it.
Although an
abundance of research has been conducted with respect to
asbestos, many unanswered questions appear to hold the key
to ultimate control of asbestos-related diseases.
The current health standard allows for an exposure
level to asbestos dust based largely upon assumptions drawn
from data extrapolated from short-term animal studies.
It
appears difficult to accept these "ballpark guesstimates"
used as health guidelines when the number of deaths attributed to asbestos exposure continues to rise.
There is a clear need for urgent studies on the biological effects of the various types of asbestos in order to
better identify its specific toxicity.
Current opinions
point to the fact that the pathogenicity of fibrous asbestos
dust appears to be determined by its mechanical irritation
and synergistic action with known co-factors.
Of equal importance, is the need for epidemiological
studies to be conducted along with environmental sampling
studies, so a correlation between medical findings and
carefully documented airborne concentration levels can be
drawn.
66
Q
Lastly, realistic limits must be established or
changed when appropriate, so as to reveal the beginning
biological changes in a worker which signal illness.
These
limits should be the most sensitive and signicant indicator
of potential i l l health which are likely to appear in a
worker.
The airborne asbestos dust levels measured in this
survey indicate that the sawing and drilling operations
constitute an imminent hazard to the health and well-being
of the workers being exposed.
In order to eliminate the hazard, it is recommended
that the need for this specific material be reviewed and an
alternate, less toxic material be substituted in its place,
if possible.
If it is not feasible to substitute for the material,
local exhaust ventilation systems and
monitoring program must be instituted.
a
comprehensive air
The local exhaust
controls are required for the bandsaw and drilling operations at the Capistrano Test Site and ATC Laboratory.
In line with the above mentioned requirements, the medical program for biological monitoring of employes must be
continued and upgraded.
This would assure that all employes
required to work with phenolic asbestos receive a preplacement physical and a routine physical thereafter at
intervals not to exeed 12 months in duration.
An educational training program should also be formulated in order to advise employes of the hazards associated
'
67
with asbestos dust and how to minimize their exposure to it.
Familiarization of the employe with the material and appropriate control measures should be an important phase of the
educational training program.
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Asbestos and Asbestos -· Related Diseases - Occupational
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Technical Symposium. Personal notes.
Bayer, S. G. and R. D. Zumwalde. 1973. Sampling and
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Services.
Chiappino, G. and G. Briatico-Vangosa. 1973. The Early
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Cooke, w. E. 1927. Pulmonary Asbestosis.
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Brit. Med. ,
Cooper, C. W. 1967. Asbestos As a Hazard to Health.
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Arch.
Dixon, J. R. 1970. The Role of Trace Metals in Chemical
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Dowben, R. M. 1971. Cell Biology.
lishers, New York.
Harper and Row Pub-
Edwards, G. H. and J. R. Lynch. 1968. The Method Used By
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Elmes, P. C. and J. C. Simpson. 1971.
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Fleming, A. J., C. A. D'Alonzo and J. A. Zapp. 1960.
Modern Occupational Medicine, 2nd Edition. Lea and
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68
69
Hammond, E. c. and I. J. Selikoff. <1972.<<- Relation of
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Johnstone, R. T. and S. E. Miller.
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Lynch, J. R. and H. E. Ayer.
1968. Measurement of
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Manhatten, Raybestos; Inc.
1963. Engineering and Design
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1949. Asbestosis and Carcinoma of
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70
Patty, F. A.
1958.
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Ann. Occup. Hyg. 15:61-64.
Appendix 1
Brief Medical Histories of Employes
Exposed to Phenolic Asbestos
71
72
Employe (G. H.)
Age:
47
Height:
70"
Date of
Examination
Years employed:
Vital Capacity
Percent of Normal
15
Chest X-Ray Results
1/24/61
Not taken
Presence of calcified left hilar
nodes
3/14/62
Not taken
Same as 1/24/61
9/11/63
103
Same as 1/24/61
4/3/68
10/25/68
81
Clear normal x-ray
84
Clear normal x-ray
10/10/69
78
6/8/70
12/24/70
94
92
Clear normal :x-ray
Clear normal x-ray
8/11/71
96
12/16/71
96
Clear normal x-ray
Clear normal x-ray
6/8/72
94
Clear normal x-ray
12/29/72
94
6/12/73
92
Clear normal x-ray
Clear normal x-ray
1/17/74
89
Clear normal x-ray
Occupation:
Rocket Site Technician
Previous Exposure to Asbestos:
Smoker:
No.
Clear normal x-ray
No
73
Q
·····Employe .. (L .H.)··
Age:
42
Height:
71"
Years employed:
15
Vital Capacity
Percent of Normal
Chest X-Ray Results
6/7/61
Not taken
Clear normal x-ray
9/19/63
104
Clear normal x-ray
7/29/64
110
Clear normal x-ray
2/18/65
106
Clear normal x-ray
8/20/65
100
Clear normal x-ray
3/10/66
99
Date of
Examination
Linear opacities
base of left lung
Not taken
6/20/66
Clear normal x-ray
(infiltration gone)
10/26/66
96
Clear normal x-ray
4/28/67
95
Clear normal x-ray
ll/28/67
89
Clear normal x-ray
5/15/68
87
Clear normal x-ray
l/31/69
87
Clear normal x-ray
8/15/69
87
Clear normal x-ray
2/27/70
82
Clear normal x-ray
l/14/71
102
Clear normal x-ray
8/ll/71
102
Clear normal x-ray
l/15/72
108
Clear normal x-ray
6/5/72
102
Clear normal x-ray
12/19/72
102
Clear normal x-ray
l/4/73
102
Clear normal x-ray
6/12/73
102
Clear normal x-ray
1/8/74
95
Clear normal x-ray
6/13/74
93
Clear normal x-ray
2/18/75
95
Clear normal x-ray
Occupation:
Rocket Site Technician
Previous Exposure to Asbestos:
Smoker:
No
No
'
74
Employe ( C . D.)
Age:
55
Height:
73"
Date of
Examination
Years employed:
Vital Capacity
Percent of Normal
Not taken
6/20/66
Chest X-Ray Results
Normal chest
Not taken
83
1/5/70
13
Few calcifications
noted in both hilar
areas
12/7/72
101
7/31/73
99
Few calcifications
in right hilum
2/5/74
99
Same as before/
normal
6/27/74
91
Same as before/
normal
1/21/75
91
Same as before/
normal
Occupation:
Machinist
Previous Exposure to Asbestos:
Smoker:
Yes
Yes
75
Employe
Age:
47
Height:
69"
Date of
Examination
Years employed:
Vital Capacity
Percent of Normal
Not taken
Not taken
1/26/61
2/28/62
1/16/64
Normal
Normal
Normal
Normal
Normal
Normal
Normal
Normal
86
84
81
99
96
84
80
3/16/71
1/17/74
3/4/75
Occupation:
Previous Exposure to Asbestos:
No
Normal
Normal
Normal
Rocket Site Technician
No
15
Chest X-Ray Results
Normal
Not taken
104
92
7/23/65
ll/4/6E
11/28/67
10/4/68
12/12/69
12/21/71
Smoker:
'{A.~D.)
76
Age:
47
Height:
70"
Date of
Examination
Years employed:
Vital Capacity
Percent of Normal
15
Chest X-Ray Results
1/24/61
Not taken
Calcified left
hilar nodes
3/14/62
Not taken
Same/normal
9/11/63
103
Same/normal
4/12/68
81
84
Same/normal
Same/normal
10/29/68
3/25/69
Not taken
Same/normal
11/10/69
Same/normal
1/19/71
78
94
92
8/20/71
96
Same/normal
12/21/71
Same/normal
6/15/72
95
94
12/29/72
94
Same/normal
6/21/73
92
Same/normal
1/17/74
89
Same/normal
7/1/74
88
Same/normal
6/22/70
Occupation:
No
Same/normal
Same/normal
Rocket Site Technician
Previous Exposure to Asbestos:
Smoker:
Same/normal
Yes
77
Employe (H. K.)
Age:
52
Height:
70"
Date of
Examination
Years employed:
Vital Capacity
Percent of Normal
8/25/61
Not taken
12/19/61
11/5/62
9/18/63
9/2/64
Not taken
Not taken
9/23/64
10/22/64
Not taken
Chest X-Ray Results
Right hilar calcifications with
right apical
fibrosis
Same as above
Same as above
Same as above
Streak of parenchymal thickening or
pleural thickening/
area of
inflammation
90
Not taken
Same as above
Same as above
Same lines of
increased density
assumed to be scars
in the pleura and
parenchyma
Not taken
Not taken
2/26/65
14
Same as above
7/14/65
10/14/66
Same as above
10/31/67
Same as above
10/1/68
12/12/69
10/8/70
2/15/71
3/28/72
4/24/73
5/6/74
4/22/75
Same
Same
Same
Same
Same
Same
Same
Same
Occupation:
Rocket Site Technician
Previous Exposure to Asbestos:
Smoker:
No
Yes
as
as
as
as
as
as
as
as
above
above
above
above
above
above
above
above
78
Employe
Age:
35
Height:
70"
Date of
Examination
(J. L.)
Years employed:
Vital Capacity
Percent of Normal
Chest X-Ray Results
7/5/61
11/21/67
6/11/68
2/3/69
9/3/69
4/8/70
10/28/70
4/23/71
Not taken
110
111
111
111
Normal
Normal
Normal
Normal
Normal
Normal
Normal
Normal
12/21/71
7/6/72
110
109
Normal
Normal
12/19/72
111
Normal
7/12/73
111
Normal
1/17/74
109
Normal
6/7/74
108
Normal
105
111
112
Occupation:
Rocket Site Engineer
Previous Exposure to Asbestos:
Smoker:
No
No
10
79
Employe (A.M.J
44
Height:
69"
Age:
Date of
Examination
6/26/61
8/4/64
7/14/65
(special
chest
x-ray)
Years employed:
Vital Capacity
Percent of Normal
14
Chest X-Ray Results
Not taken
Normal
103
Not taken
Normal
Pleural diaphragmatic adhesions
(history of
pleurisy between
1961-64)
ll/9/66
94
Same as above
10/17/67
90
Same as above
12/18/69
79
Same as above
Occupation:
Rocket Site Technician
Previous Exposure to Asbestos:
Smoker:
No
No
80
@
-.
Employe (S. 0.)
Age:
53
Height:
66"
Date of
Examination
Years employed:
Vital Capacity
Percent of Normal
Chest X-Ray Results
1/26/61
Not taken
Normal
9/18/63
Not taken
Normal
6/22/65
93
Normal
11/9/66
80
Normal
11/9/67
86
Normal
10/18/68
79
Normal
12/5/69
81
Normal
5/3/71
91
Normal
11/14/72
80
Normal
8/23/73
83
Normal
9/5/74
74
Normal
Occupation:
Rocket Site Supervisor
Previous Exposure to Asbestos:
Smoker:
No
No
15
'
81
Employe (D. D.)
Age:
58
Height:
68"
Date of
Examination
Years employed:
Vital Capacity
Percent of Normal
Chest X-Ray Results
4/5/66
81
Normal
4/12/66
81
Normal
1/9/73
70
Normal
1/18/73
2/15/74
68
Normal
Normal
65
Occupation:
Machinist
Previous Exposure to Asbestos:
Smoker:
Yes
Yes
15
82
Employe (L. M,J
Age:
58
Height:
71"
Date of
Examination
Years employed:
Vital Capacity
Percent of Normal
12
Chest X-Ray Results
2/11/64
Not taken
Normal clear lung
field
8/25/66
Not taken
Left and right
hilar
calcifications
1/9/73
8/14/74
100'
Employe examined by personal doctor. Diagnosis:
Carcinoma right lung, pneumonectomy performed.
Employe died 1974.
Occupation:
Machinist
Previous Exposure to Asbestos:
Smoker:
Same as above
Yes
Yes
83
)
Age:
46
Height:
71"
Date of
Examination
Years employed:
Vital Capacity
Percent of Normal
14
Chest X-Ray Results
9/22/67
82
Hilar
calcifications
both sides
5/8/68
82
Same as above
1/27/68
75
Same as above
6/12/69
Same as above
2/3/70
76
73
8/17/70
88
1/22/71
92
8/27/71
91
5/1/72
1/15/73
90
85
Same as above
Same as above
5/24/73
87
Same as above
12/4/73
85
Same as above
5/23/74
82
11/29/74
89
Same as above
Same as above
Occupation:
No
Same as above
Same as above
Same as above
Machinist
Previous Exposure to Asbestos:
Smoker:
Same as above
Yes