Policy Analysis No. 263

EPA’s Cancer Risk Guidelines: Guidance to Nowhere

By Michael Gough and Steven J. Milloy
November 12, 1996

Executive Summary

The Environmental Protection Agency claims that implementation of proposed revisions to its guidelines for conducting cancer risk assessments would result in risk estimates based on the best available scientific knowledge and encourage development of new, relevant science. In fact, the proposed guidelines represent a setback for public health, science, and the EPA cancer risk assessment process.

First, the proposed guidelines would remove the existing requirement that epidemiologic studies be statistically significant before they are relied on to establish cause-and-effect relationships between chemical exposures and cancer.

Second, the guidelines maintain a number of default assumptions that have no scientific justification and dictate inflated risk estimates.

Third, although the guidelines provide for the use of other assumptions under certain conditions, no clear guidance is provided about what kind of data can overcome reliance on the default assumptions. Moreover, adoption of different assumptions may make little difference to risk estimates.

This analysis of the proposed guidelines demonstrates that the EPA needs to move from “how many rats get cancer from massive doses of chemicals?” to “what realistic public health benefits can and should be produced through regulatory programs that cost billions of public and private dollars each year?” Until Congress recognizes the legitimacy of the latter question and holds hearings, arguments about regulatory changes will deal with minutiae while gigantic regulatory costs pile up with no expectation of improvements in public health.

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Michael Gough is director of science and risk studies at the Cato Institute. Steven Milloy is president of the Environmental Policy Analysis Network in Washington, D.C.