Some Public Policy Problems with the Science of Carcinogen Risk Assessment

Abstract

Government agencies and private risk assessors use (quasi) scientific “risk assessment” procedures to try to estimate or predict risks to human health or the environment that might result from exposure to toxic substances in order to take steps to prevent such risks from arising or to eliminate the risks if they already exist We might think of this as an aspect of “regulatory science”.Using carcinogen risk assessment as a model I consider several aspects of risk assessment—use of epidemiology, animal bioassays, and extrapolation models in predicting risks—to show how scientific procedures and uncertainties may determine (in a way often unbeknownst to the practitioners) the public policy debates concerning the estimation of risks from carcinogens.For one thing, actual and possible scientific uncertainties are large enough that two different researchers using exactly the same data could come to quite different conclusions; such uncertainties permit risk assessors in large measure to determine regulatory decisions even though this exceeds their authority.