Environmental Risk Analysis: A Review of Public Policy Issues VII

98-618 ENR

CONTENTS FOR THIS SECTION

Risk Assessment Methods

Legislative Activities

Legislation

Risk Assessment Methods. Environmental risk analysis is a relatively new and immature field, and this is evident in the state of development of its methods. The most developed and well established analytic methods probably are those concerning acute effects; for chronic effects, the most developed are those used to assess human cancer risks of chemicals. These methods evaluate and model the results of animal experiments and human studies to estimate the risk that people will develop cancer following various levels of exposure to individual chemicals. Many of EPA's environmental standards, emission limits, and quality criteria are based on the results of cancer risk assessment. Other categories of risks, such as developmental risks and immunotoxicity are rarely assessed.

Even cancer risk assessment is beset by the absence of scientific data and theories. The scientific judgments and inference choices that are used to fill these gaps are controversial, because they are shaped by a scientist's values, different scientists have different values, and different choices lead to different risk estimates. Many social scientists who study technical controversies believe that "ostensible disputes over the science are, in reality, over the values inherent in the assumptions."69 The NAS has identified at least 50 inference choices required in conducting a cancer risk assessment that cannot be made on a scientific basis, and many of these decisions have strong implications for public policy. For example, analysts must determine how much evidence is enough to conclude that a chemical is a possible human carcinogen. Some want strong evidence prior to classification; they prefer to err, if necessary, by withholding judgment until they are sure a problem exists. Others would act on the first available evidence; they prefer to err on the side of alerting public officials to a possible risk.

To reduce the influence of values on individual risk estimates and to ensure that the assumptions and inferences choices made by agencies are clearly expressed, NAS has suggested that federal agencies should develop and adopt guidelines for risk assessment. EPA adopted the first guidelines for cancer risk assessment in 1977. revision was promulgated in 1986, and a second revision is in progress.

EPA also established guidelines in 1986 for analyzing: the risk that a chemical will cause mutations affecting future generations or damage to human development; human exposure to a chemical; and human health risks of chemical mixtures. The Agency revised its guidelines for developmental toxicants in 1991 and for exposure in 1992. Guidelines for assessing risks to reproduction were issued in 1996, and the Agency issued final guidelines for assessing risks of ecological effects and neurotoxicity in 1998. No guidelines are established for assessing the risk of a chemical's adverse effects on the respiratory or immune systems, or for other lethal and sublethal effects.

Guidelines are necessary to ensure that risk assessments are conducted consistently and, therefore, are more easily evaluated by independent experts. (Independent evaluations of risk assessment by qualified experts, or peer review, are the traditional means by which scientists ensure adherence to professional standards of quality in practice.) However, guidelines do not ensure that equally competent scientists will agree with the risk estimates produced by the process. In fact, some scientists criticize EPA's risk estimates for carcinogens because they do not agree with the guidelines or they think different rules should apply to certain chemicals. Controversy surrounds risk assessment only partly because the field is so young that its methods have not been studied thoroughly and adequately validated. NAS concluded in its 1983 report:

Dissatisfaction with the actions of federal regulatory' agencies is often expressed as criticism of the conduct and administration of the risk assessment process. The Committee believes that the basic problem in risk assessment is the sparseness and uncertainty of the scientific knowledge of the health hazards addressed, and this problem has no ready solution. The field has been developing rapidly, and the greatest improvements in risk assessment result from the acquisition of more and bet~er data, which decreases the need to rely on inference and informed judgment to bridge gaps in knowledge.70

Thus, controversy will not disappear when risk analysis matures, because it grows inevitably from value judgments based on different ethical systems and inference choices embodied in agencies' science policies which make risk assessment possible as well as from the special interests that stakeholders have in EPA's risk estimates.

Legislative Activities

Legislation

More than a dozen bills and amendments on environmental risk analysis were introduced in the 1O3rd Congress. One was enacted, but it applied to the Department of Agriculture, not EPA. Nine other bills were passed by one chamber or reported by the committes of jurisdiction.

The House Republican Contract with Amenca promised that within the first 100 days of the 104th Congress risk legislation would be introduced, debated, and voted upon in the House. The House passed H.R. 9 which included risk provisions in Division D, on March 3, 1995, but the bill was not debated in the Senate. The Senate reported three bills (S. 281, S. 333, and S. 343), which later were merged and introduced on the Senate floor as a substitute amendment for S. 343. However, Congress adjourned without enacting comprehensive requirements for risk analysis in the development of regulations or agency budgets. Congress did enact risk-based provisions included in major legislation addressing drinking water (P.L. 104-182) and food safety (P.L. 104-170), as well as requirements for economic analysis. Economic analysis of environmental regulations undoubtedly will involve some analysis of risks, because risk reduction is an important measure of benefits. The Unfunded Mandates Reform Act (P.L. 1044) was enacted. It requires analysis of costs and benefits of all proposed and final rules with an expected cost of $100 million or more. It also requires agencies to promulgate the alternative that is least costly, most cost-effective, or least burdensome, or to explain why such an alternative was not adopted. Congress also mandated economic analysis of federal regulations in the Small Business Regulatory Enforcement Fairness Act of 1996 (P.L. 104-121, Title II).

The 105th Congress is considering risk-based provisions included in proposals reauthorizing Superfund (Senate-reported 5.8, H.R. 2727, H.R. 2750, and H.R. 3000) that would require selection of remedies for contaminated sites to be based on site-specific risk assessments. The most comprehensive risk legislation, S. 981, as reported by the Senate Committee on Governmental Affairs, has bi-partisan support (S. Rept. 105-188). It would require agencies to evaluate and compare costs, benefits, and risks when proposing or promulgating environmental rules expected to have an impact of at least $100 million a year in costs on the national economy. S. 981, as reported, also would require a systematic comparison of risks to health, safety, and the environment. Less comprehensive H.R. 2451/S. 599, as introduced, would require EPA to evaluate environmental health risks to vulnerable sub-populations in all risk assessments and regulatory decisions. House-reported H.R. 1704 (S.1675 in the Senate) would establish a Congressional Office of Regulatory Analysis to conduct regulatory impact assessments on major rules and on non-major rules at the request of a Member of Congress (H.Rept. 105-441). For more information on these or other proposals in the 105th Congress, see the CRS Issue Brief The Role of Risk Analysis and Risk Management in Environmental Protection (IB 94036).

ENDNOTES

69 Rushetsky, Mark E. "Assuming the Conclusions: Risk Assessment in the Development of Cancer Policy." Politics and the Life Sciences, v.4, (August), 1986. p.31.