Occup. Met). Vol. 50, No. 4, pp. 217-220, 2000
Copyright © 2000 Lippincott Williams & Wilkins (or SOM
Printed in Great Britain. All rights reserved
0962-7480/00
IN-DEPTH REVIEW
Occupational and environmental
medicine: moving the factory fence
or hedging our bets?
P. G. Lewis
Rohm and Haas Company, Philadelphia, USA
Occupational and environmental medicine evolved out of concern for the effect of work
hazards on health. The experienced gained in considering such hazards has been
extended to understanding general risks in the environment. As we look toward the
future, classical occupational and environmental hazards such as over exposure to
lead, asbestos and mercury are waning and being replaced by concerns around
sustainable development, toxicology testing and exposure information for high
production volume chemicals, development of better approaches for setting workplace
and community exposure limits, environmental justice and many others. The
opportunities for the future exist in overcoming these new challenges.
Key words: Chemical testing; endocrine disruption; environmental justice; ergonomics;
exposure limits; hormesis; HPV/SIDS; material safety data sheets; multiple chemical
sensitivity; OECD; sustainable development.
Occup. Med. Vol. 50, 217-220, 2000
INTRODUCTION
For quite some time now, we have understood the
importance of work and the potential hazards associated
with it. Occupational and environmental medicine
evolved out of concern for the effect of work hazards
on health.1 More recently, the experience gained in
considering such hazards has been extended to help us
understand and minimize potential negative effects from
more general environmental exposures.2 There has been
a tendency for many to think of past times as being very
different, very much better than today. It is common,
among some, to imagine people in the past working and
living safely and healthfully in green pastures surrounded
by clean air and water. Yet we know that was not the
character of the past and when one considers the
improvements in longevity and quality of life associated
with the arrival of the industrial revolution and the great
disparity in health between the most industrialized and
the least industrialized nations in the world, it is unlikely
that we will ever be successful in convincing the vast
majority of humanity to 'go back' to those 'idyllic' times.3
It appears our best chance for capturing the 'purity of
intent' of times long ago, and yet the advantages of the
present, is to persuade much of the population to head in
the direction of even greater development-sustainable
Correspondence to: Dr Phil Lewis, 100 Independence Mall West,
Philadelphia, PA 19106-2399, USA.
development.4 Herein lie both the challenges and the
great opportunities for occupational and environmental
medicine, but it will take some change on our part.
Many training programmes prepare occupational and
environmental physicians for a world that is quickly
passing away. The days of poisoning from lead, asbestos
and mercury are waning.5 That is not to say that classic
industrial and environmental hazards will not be with us
for some time, just that they are well known, fairly well
understood and the challenge is mainly a mopping-up
action. There are still some countries and some selected
work areas of nearly every country where threats from
heavy metals, pesticides and mining hazards exist,6 but at
least we know how to deal with them and the real
question for the future with regard to these problems will
be how safe is safe enough. On the horizon though are
new problems, some of which we have yet to recognize
and some we do not understand. The contributions of
occupational and environmental medicine to society will
depend on our ability to keep the momentum going in
eradicating the hazards we know, having an eye for the
problems coming at us and finding solutions for both
which the society will accept and implement.
SUSTAINABLE DEVELOPMENT
For a concept that 20 years ago was virtually unknown,
sustainable development has come to occupy the
thoughts of many in academia, industry, government
218 Occup. Med. Vol. 50, 2000
and the general public.7'8 Given its sweeping impacts on
society and industrial development in particular, it is
imperative that we understand the concept and what is
being done about it. It is difficult to know when
sustainable development as a thought or movement
began. Certainly the writings of Thomas Robert Mai thus
in 1798 did much to bring to the attention of at least
those in western Europe and North America concerns
around the limitations of the environment to support a
burgeoning human population. Though his view that
human population growth will always tend to outrun the
growth of production has been tempered by the
increased efficiency of production in the last part of the
twentieth century, and our ability to use fuels other than
coal, wood and oil, his concern that we must look at: the
balance between population growth, production and the
environment seems to be right on the mark.9 Though
defined differently by different groups and individuals a
useful definition of sustainable development can be
found in the President's Council on Sustainable Development report.10 The idea of addressing environment,
economy and equity in one fell swoop is powerful. It
means that nations and individuals are coming to
recognize that industrial development must proceed in
a way that is safe and fair for as many people as possible,
if not everyone. The implications for occupational and
environmental medicine are enormous. It means we will
not be alone in trying to find safer ways to work and
exist, but it also means that solutions we come up with
must be practical and take into consideration the greater
good.
HPV/SIDS
Thirty years ago the Organization for Economic Cooperation and Development (OECD), a group which
grew out of cooperation around the Marshall Plan in
Europe after World War II, developed a plan for the
testing of high production volume (HPV) chemicals
through a group of tests, mainly toxicological, known as
the screening information data set (SIDS). Over the
years, however, squabbles between countries over who
should bear the cost of the testing resulted in little if
anything getting done. In the summer of 1997, the
Environmental Defense Fund (EDF) sent a letter to the
100 largest chemical companies in the US demanding
SIDS testing protocols be completed for all chemicals
made or imported into the US in quantities of 1 million
pounds (weight) or more and the resulting data published
by March 2000. The result of the EDF challenge has been
an agreement between the US Environmental Protection
Agency (EPA) and the Chemical Manufacturers' Association (CMA) to complete the testing for about 3000
HPV chemicals by the year 2004 with general availability
of the data being provided over the internet.'' A more
expansive initiative is moving along rapidly under the
auspices of the International Council of Chemical
Associations. For the first time in history there will soon
be toxicological data on many, if not most, of the
chemicals in commerce. It is easy to imagine that the
existence of such data will result in some very hazardous
materials being removed from the marketplace, but more
importantly more rational decisions being made on how
to safely live and work with these very important materials
which have so benefited society.
EXPOSURE LIMITS
Since at least the days of Ramazini, we have known that
the dose, or exposure, makes the poison. From sunshine,
to vitamins, to industrial materials there is a range of
human and environmental responses to different levels of
exposure. Hence the idea of exposure limits. There is
general agreement that there are hazards as well as
benefits from industrial materials and that it is best to
manage our exposures so they are safe. But what does
that mean? The American Council of Governmental
Industrial Hygienists (ACGIH) has since 1945 been a
respected source for exposure limits on industrial
materials. Their definition of safe, though safe for nearly
all workers, may not be sufficient in the future.12 In many
countries, the ethos of sustainable development means
that most, if not all, people will be expected to work.
Many people who may be less healthy and robust to
begin with, compared to working populations in the past,
will be in the work place. The traditional approach to
setting exposure limits is the safety factor approach,
which takes a no observable or lowest observable effect
level in animals and on the basis of conversion factors,
safety factors and professional judgment levels are set.13
Setting an exposure limit this way certainly produces
levels that are generally regarded as safe for nearly all
workers, but it does not allow one to know what number
or percentage of the population may not be protected
and why. Over the next several years, a quantitative risk
approach for setting exposure limits will probably be
explored. The quantitative risk approach starts with the
same animal data and conversion factors, but uses the
available data to estimate the quantitative level of risk
presented at different levels of exposure. These estimated levels of exposure risk are then compared to levels
of acceptable risk or guidelines determined by society
and levels are set to ensure they are below these
acceptable risk guidelines. The clear advantage to this
technique is it quantifies the amount of residual risk,
allows identification of areas where improved science
and data will help us to set better exposure levels and
allows an understanding of where we need to most direct
our health protection and production improvement
resources.
ENDOCRINE DISRUPTION/MULTIPLE
CHEMICAL SENSITIVITY/HORMESIS
These three apparently disparate concepts are actually
important areas of debate about what is happening at
levels of exposure that are below those at which we
normally test or have data. Endocrine disruption and
multiple chemical sensitivity both argue that animals and
P.G. Lewis: The future of occupational and environmental medicine
humans when exposed to low doses of either single or
multiple chemicals develop and display reactions that are
detrimentally different from those seen at doses for
which toxicology testing data is available.14'15 These
reactions may be either respiratory distress, immune,
endocrine or developmental system abnormalities or
cancer. Hormesis on the other hand calls our attention to
a phenomenon with which we are already familiar: some
materials have a U shaped dose-response curve, the
most recently discussed being ethanol.16'17 The question
yet to be answered is how many, if any, have other
materials generally in commerce is a dose-response
curve similar to that which we appear to be seeing for
ethanol. Recent reviews have suggested a lack of general
support in the medical community for any of these
theories, but the jury is still out. In the end, the possibility
that any one of these theories is correct will put a greater
need on gathering data on possibly harmful chemicals
and their effects on humans and the environment from
exposures at very low levels.
INFORMATION ON MATERIAL SAFETY
DATASHEETS
The general availability of material safety datasheets
(MSDS) has greatly improved the management of the
workplace and the environment toward lower risks.18
Efforts at the national and international level to bring
harmonization to the format and information present on
the MSDS are ongoing and will further improve life for
us all. That said, the coming debate will be on the degree
to which companies are required to publish exposure
levels (workplace, ambient air, community, drinking
water and others) on their sheets. Testing protocols such
as SIDS are difficult to negotiate and even more difficult,
as we have seen, to implement. Additionally, our
understanding of animal, human and environmental
responses to materials is likely to out pace our ability to
get national or international agreements on testing
protocols. Currently the practice of several large
companies, the publication of exposure levels on MSDS
has several potential benefits.
First, publication of exposure limits allows anyone in
society to discuss the reasonableness of the degree of
safety provided by the limit. This, along with the need to
be able to produce the necessary data to explain the limit
published, is likely to result in more testing and data
gathering around materials in commerce. Also, because
the generation of such testing and data will be in the
hands of the producers, it will probably be targeted to
those areas where the science is weakest and where the
biggest bang is had for the proverbial buck.
219
ment Corporation after a study showed that from the
early 1920s to the late 1970s all of the city's governmentowned landfills and six of Houston's eight garbage
incinerators had been located in communities that were
predominately black. Further work by many has shown
an association between groups disadvantaged because of
ethnicity, race or economics and the likelihood of living
near higher risk industrial process.19 What is not
understood is the degree to which suspected health
problems in the neighbourhoods of concern and living
around higher risk industrial process is linked. What is
probably true is that the relative lack of political and
economic power in these neighbourhoods does set them
up for even greater numbers of high risk industrial
processes in their living areas. Answering the question of
to what degree effects of materials at low doses outweigh
the concomitant effect of life style differences in
neighbourhoods and populations of concern will require
the expertise of occupational and environmental physicians, along with many other professionals and the
neighbourhoods themselves, to sort out. While concerns
around environmental justice are presently talked about
most in the US, essentially the same set of concerns are
being addressed under the aegis of sustainable development because similar concerns exist between wealthy and
less wealthy nations, and wealthy and less wealthy
individuals within nations. Given the slowness or total
lack of equitable distribution of wealth in many
countries, environmental justice problems will probably
be a concern of most nations for the foreseeable future.
ERGONOMICS
There is little to say about ergonomics that you will not
have heard before. Continuing controversies over reliable
diagnostic criteria and effective treatments will hopefully
be settled soon.20"22 Perhaps the most interesting aspect
of ergonomics is the degree to which it raises the question
of work fitness and leads directly to discussions of areas
where occupational and environmental medicine's contributions may easily overshadow anything else we may
do for the next several decades: the question of improved
creativity and productivity. Prevention of ergonomic
injuries is beginning to generate discussion on how we
can best help our brothers and sisters on the planet be
more physically, mentally and emotionally robust, better
able to handle the stesses associated with work and the
environment until non-productive stresses can be engineered out. Learning from these efforts will surely help
all humankind be the best we can be.
SUMMARY
ENVIRONMENTAL JUSTICE
The dawn of a new millennium, with all the attendant
fears and opportunities, some real some imagined, is, if
nothing else, exciting. Occupational and environmental
In 1979, a community in Houston Texas brought suit
(Bean v. Southwestern Waste Management Corp., 482 F. medicine has contributed mightily to the quality of life in
the present era. Mindfulness of developing areas of
Supp. 673 [S.D. Tex. 1979]) against the Texas
concern and opportunity such as those discussed herein
Department of Health and the Southwestern Manage-
220
Occup. Med. Vol. 50. 2000
will certainly require that we go beyond the factory fence.
Yet doing so will also mean we will have properly hedged
our bets against irrelevance and obsolescence, the bane
of any specialty.
11.
12.
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