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OCR for page 9
InI;roduction
Through Congress the American public has granted author-
ity to Federal administrative agencies to restrict private
actions, such as the production and use of chemicals,
when this is deemed necessary to protect the health of
the public. The 1970 s are notable for the large number
of new federal regulatory laws that are applicable to the
environment, both in the workplace and in the community.
These laws reflect a dramatic and relatively rapid shift
in public priorities toward the protection of health.
Concurrently with shifts in social priorities, advances
in science have contributed to policy problems, for the
advances have revealed the extent of the environmental
health problem. Some earlier regulatory programs had
addressed exposure to toxic chemicals, but they were
directed mainly at the risk of poisoning and other acute
effects. Much policy-mak~ng related to such effects
involved routine, short-term, acute animal studies to
establish ~no-observed-effect" doses and then the
straightforward calculation of allowable hen exposure
based on the application of safety factors to relatively
uncomplicated scientific findings. Such an approach
reflected little recognition of problems that might be
associated with smaller exposures. Cancer, birth defects,
and other conditions were seldom seen as preventable by
government intervention. Only in the last 15 years has
the potential extent of the linkage between such condz-
t ions and toxic substances been revealed. The often-
c~ted estimate that a large fraction of all cancers may
be attributed to human exposure to toxic agents (including
smoking, diet, lifestyle, and occupation) originated
f airly recently (Boyl and, 1969 ; }~gginson, 1969), and it
9
OCR for page 10
lo
was not until the 1970s that regulatory agencies focused
their attention on cancer and other chronic health risks.
Scientific advances entered the picture in a second
way. The technology that has made it possible to detect
relations between particular agents and cancer or other
chronic effects has evolved rapidly from the days when
exposure through skin~pa~nting and subcutaneous inj action
care re~'ea on in animal tests of carcinogenicity. }n-
creasingly, ep~dem~otog~c investigations have earner
confirmed the findings of animal experiments of provided
evidence that linked exposures to particular chemicals to
particular chronic health effects. The introduction of
reliable testing methods resulted in broader government
testing requirements and, steadily, the discovery of more
and more suspect chemicals--many of them in common use~-
that demanded agency attention. The techniques are still
developing, and we are still looking for better ways to
design and interpret annoy bioassay experiments.
The increase in newly suspect chemicals was accompanied
by the development of instruments and procedures That
permitted the detection of chemicals at lower and lower
concentrations. Even if the number of suspect chemicals
had not increased dramatically, these sensitive detection
methods would have revealed the presence of such chemicals
in concentrations that earlier methods would have missed.
Combined with all those changes were the development and
refinement of analytic methods of estimating the degree
of human risk on the basis of data from hewn studies and
~ ~ _
ant mad expert menus .
Public policies are not immediately adaptable to rapid
changes in social priorities and scientific advances.
Many of the fundamental difficulties of regulatory risk
assessment result from attempts to bend old laws and
policies to fit newly perceived risks. For instance:
· A regulatory framework based on she traditional
approach involving norobserved-e~fect doses and safety
factors is now being applied to health effects for which
a no-effect dose cannot be demonstrated, except at zero
exposure.
· Regulatory laws and programs designed for the
elimination of what was understood to be the very rare
event of chronic hazard now operate in the presence of
the recognition that many agents are suspect.
· Agencies must evaluate hundreds of chemicals on
which no data related to human risk are available and on
OCR for page 11
11
which few animal tests were required and many other
chemicals that were tested with methods that do not meet
modern standards.
.
Laws were written and programs designed before
current quantitative methods for estimating human risks
on the basis of data from animal studies were developed.
DIFFICULTIES IN DECISION—WRING
Agency decisions regarding potential carcinogens and
similar hazards are commonly beset by two types of dif-
ficulties: inherent limitations on the power of analysis
and practical constraints imposed by external pressures.
Several such factors are particularly relevant to the
consideration of scientific aspects of risk assessment.
INHERENT LIMITATIONS
Uncertaintv
The dominant analytic difficulty is pervasive uncertainty.
Risk assessment draws extensively on science, and a strong
scientific basis has developed for linking exposure to
chemicals to chronic health effects. However, data may
be incomplete, and there is often great uncertainty in
estimates of the types, probability, and magnitude of
health effects associated with a chemical agent, of the
economic effects of a proposed regulatory action, and of
the extent of current and possible future human exposures.
These problems have no Immediate solutions, given the
many gaps in our understanding of the causal mechanisms
of carcinogenes~s and other health effects and in our
ability to ascertain the nature or extent of the effects
associated with specif ic exposures. Because our knowledge
is limited, conclusive direct evidence of a threat to
human health is rare. Fewer than 30 agents are definitely
linked with cancer in humans (Tomatis et al., 1978); in
contrast, some 1,500 substances are reportedly carcino-
genic in animal tests, although they include substances
tested in studies of questionable experimental design.
We know even less about most chemicals; only about 7,000
of the over 5,00O,000 known substances have ever been
tested for carcinogenicity (Maugh, 3978)--a small fraction
of those theoretically under regulatory Jurisdiction. We
OCR for page 12
12
know still
cancer.
about chronic health effects other than
Ethical considerations prevent deliberate human experi-
mentation with potentially dangerous chemicals, and the
length of the latent period for cancer and some other
effects greatly complicates epidemiologic studies of
uncontrolled human exposures. Animal models must be used
to investigate whether exposure to a chemical is related
to the incidence of health effects, and the results must
be extrapolated to humans. To make judgments amid such
uncertainty, r Ask assessors must rely on a serf es oF
assumptions .
Limited Analytic Resources
The number of chemicals in the jurisdiction of federal
regulatory agencies is enormous. For example, of the
roughly 5, 000, 0 00 known chemicals, more than 70,000 are
in commercial use (Fishbe~n, 1980). The Environmental
Protection Agency's Chemical Activities Status Report
lists about 3, 500 chemicals as being under some sort of
active consideration in the Agency's various regulatory
programs. Similarly, the Food and Drug Administration's
food program must cope with over 2,000 food-related chemi-
cals (900 flavors, 700 items listed as generally recog-
nized as safe," 350 food additives, 175 animal drugs, and
60 color additives) and an additional 12,000 indirect
additives (Flamm, 1981).
The many problem chemicals in an agency jurisdiction
compete for attention of analysts and decision-makers.
If an agency is considering new action on many substances
at once, its scientific staff is stretched thin. Most
agencies do not have the analytic resources to do a
thorough risk assessment for priority-setting anc..~st
rely on less formal methods to ensure that the highest-
risk chemicals are examined first.
Complexity
For most chemical agents that might be subject to regular
tion, a great variety of factors must be assessed, includ-
ing potential toxicity, extent of human exposure, effec-
tiveness of technologies to reduce exposure, the nature
of possible substitute chemicals, effects on and interests
of various population groups, and economic effects of
OCR for page 13
13
regulatory alternatives. Decisionrmake~s In a regulatory
agency may encounter a large amount of highly technical
information as they work toward their decisions; many
scientific disciplines and technical fields are usually
involved. An agency would like to have simple rules and
analytic procedures to ensure consistency and competence
in its decision-making, but, in the face of scientific
uncertainty, such simplicity is cliff Cult to achieve
without an inadvertent loss of crucial scientific insight
from the decision process.
EXqE:RNAL P~:SSURES
l-
Public Concern with Health Protection
When the risk involves a serious disease, such as cancer,
or birth defects, feelings are likely to run high, par-
t~cularly if the groups exposed to a chemical are mob~l-
ized to express themselves in an agency's deliberations.
Such groups insist that regulatory action need not await
conclusive evidence of cause and effect and need not be
based exclusively on the most scientifically advanced
testing methods.
Visible Economic Interests
Although it is rarely known which individuals are likely
to be saved from adverse health effects through a regu-
lation that reduces exposure to a particular chemical,
those who bear the economic costs of such restrictions
can identify themselves without any difficulty. These
parties can provide relatively concrete projections of a
prospective regulation's inflationary influence, effect
on employment, and other immediate economic effects, and
such consequences may be substantial. They may question
the wisdom of balancing concrete evidence of economic
damage against evidence of health protection that depends
on a complex series of assumptions derived from sparse
and indirect data.
Congressional Action
In fulfilling its role as the legislative voice of popular
concerns, Congress can act in ways that influence decision
OCR for page 14
~4
processes. It can dictate the factors to be included In
and excluded from decision making t the Delaney clause is
an example), and it can pass special legislation to prep
empt agency discretion, as it did in acting to prevent
the removal of saccharin from the market.
PROPOSED REFORMS
Under these conditions' it would perhaps be surprising if
calls for major reform were not heard. Some have sought
to improve the techniques that the government uses to
analyze and evaluate risks; for example, the House of
Representatives In 1982 passed H.R. 6159 (commonly known
as the fritter bills), to establish a government-wide
program of research and demonstration projects on quanta
titative and comparative risk analysis.
Much of the recent controversy is general; it reflects
the conflict in values between different groups in soc:-
ety, particularly with regard to the relative importance
of economic factors and health protection in the formula-
tion of regulatory decisions. Different groups w~11
inevitably disagree about the degree of risk (if any)
that is defined as acceptable in a particular case.
However, some criticisms directly address the risk
assessment component of the overall decisionrmaking
process. Some critics question whether current practices
adequately safeguard the quality of the scientific
interpretations needed for risk assessment. With a
scientific base that is still evolving, with large
uncertainties to be addressed in each decision, and with
the presence of great external pressures, some see a
danger that ache scientif ic interpretations i n risk
aSses=~'ents will be distorted by policy considerations,
and they seek new institutional safeguards against such
distortion.
Among the institutional reforms suggested, two major
_;: an" Who focus of this refit:
reorganization
Acid ~ =~__ ~ ~ _ ~~ _
to ensure that r isk assessments are protected f ram
inappropriate policy influences and development and use
of uniform guidelines for carrying out risk assessments.
Same argue that scientific quality, consistency, and
distinction between scientific judgment and policy 3udg-
ment can be Improved through the use of explicit guide-
lines for agency risk assessments. Such guidelines would
specify methods for interpreting scientific data and
would seek to limit analysts who confront data gaps or
OCR for page 15
IS
extrapolation questions to methods that are consistent
with the best current scientif ic judgment. Analysts
following the guidelines would find it easier to describe
systematically and explicitly the methods that are incor-
porated in their risk assessments.
Several other recent proposals call for major restruc-
turing of federal processes to separate the risk assess-
ment function organizationally from dec~szon-making. The
objectives would be to permit analysts to work indepen-
dently of policy pressures and to foster consistency of
risk assessments. Various approaches have been suggested,
including creation of a single body outside the government
for the performance or review of risk assessments, crea-
t~on of a single government unit to conduct risk assess-
ments for the entire government, and creation of separate
risk assessment units in particular programs or agencies
and systematic review of assessments by independent
scientific advisory groups.
The STODY
This report responds to a congressional request to examine
the merits of the two major types of Reform proposal. It
is the final report of the National Research Council's
Committee on the Institutional Means for Assessment of
Risks to Public Health. Chapter ~ describes the structure
of risk assessment, the role of science in the assessment
process, and current federal uses of risk assessment.
Chapter IT examines the feasibility and desirability of
the development and use of uniform guidelines. Chapter
III reviews various organizational arrangements for risk
assessment. The Committee's overall conclusions and
recommendations appear in Chapter IV.
REFERENCES
_ . _
Boyland, E. 1969. The correlation of experimental
carcinogenesis and cancer in man. Prog. Exp. Thor
Res. 77: 222 - 234 .
F i shbein, L . 1980. Potential industrial carcinogenic
and mutagenic alkylating agents, pp. 329-363. In
D. B. Walters, ed. Safe Bandling of Chemical
Carcinogens, Mutagens, Teratogens, and Highly Toxic
Substances, vol. I. Ann Arbor, Mich.: Ann Arbor
Science.
OCR for page 16
16
Flame, W. G. October 13, 1981. Remarks to the Committee
on the Institutional Means for Assessment of Risks to
Public Health.
1969.
Higginson, J. 1969. Present trends in cancer epidemi-
ology. In Proc. Can. Cancer Conf. 8:40-75.
Maugh, T. 1978. Who chooses chemicals for test ing?
Science 201:1200.
Tomatis, L., C. Ag the, B. Bartsch, 3. Buff, R. Montesano,
R. Saracci, E. Walker, and J. W~lbourn. 1978.
Evaluation of the carcinogen~c~ty of chemicals: a
review of the monograph program of I.A.R.C. Cancer
Res. 38:877.
Representative terms from entire chapter:
chronic health
