ABSTRACT
This chapter discusses risk assessment for noncarcinogens identifies some of its limitations, and examines the question of whether there is any basis for adopting for noncarcinogens the form of risk assessment used for carcinogens. Risk assessment is a routine component of decisionmaking as it relates to carcinogens. Risk assessment for noncarcinogens is different in concept and form, but it is nevertheless a risk assessment. Risk assessment for noncarcinogenic forms of toxicity, as it has been and is conducted, depends on acceptance of the threshold hypothesis for every form, just as risk assessment for carcinogens depends, at least in the regulatory context, on rejection of the same hypothesis. Some scientists reject this notion for carcinogens. There are several suggestions in the literature for adopting the form of risk assessment used for carcinogens for noncarcinogenic effects. For all noncarcinogenic forms of toxicity, it has become the custom to assume the threshold hypothesis for purposes of risk assessment.
