RISK ASSESSMENT - THE DEFAULT CONSERVATISM CONTROVERSY

EPA cancer risk assessment rests heavily on defaults. Defaults are a r eduction of science to generic principles selected as a policy matter on the basis of ''conservatism'' for use in risk assessment. Conservat ism is understood to mean a choice to avoid underestimating risk. The recent report of the National Academy of Sciences (1994) has turned th e spotlight on the controversy regarding the use of generic principles as defaults and whether conservatism is the appropriate value criteri on for their selection. Defaults had their origin in the early 1970s a nd the debate has continued regarding the scientific basis for the def aults and whether a conservatism, a value that the NAS said is ''beyon d science,'' is appropriate as a basis for the policy choices. This pa per briefly examines the CAPRA recommendations to reduce the reliance on defaults, the history of the default conservatism controversy, and EPA's initial draft response to the CAPRA recommendations. (C) 1995 Ac ademie Press, Inc.