Purpose-Driven Risk Assessment

Chemical exposures are routine; some are controlled, some are not. Whether an exposure should be controlled depends on the acceptability of the consequences of controlling or not controlling the exposure. The federal government has the responsibility to protect human health against the harmful effects of chemical exposure, and uses rather conservative policies and procedures to develop regulatory exposure standards. These protective risk values typically do not inform the likelihood of harm or the type of harm that should be anticipated if regulated exposure standards are exceeded. Exposure guideline values are not regulatory and not enforceable. Their purpose is to predict the types and severity of responses with respect to the exposure. These values may be called "predictive," perhaps primarily because of the decreased level of conservatism based directly on their need to provide information on the likelihood of harm and the type of harm that should be anticipated when exposures are uncontrolled. If an emergency response action is required, the intensity of that response should be aligned with the anticipated impact of the exposure on human health and safety. The applicability of risk values for specific exposure scenarios should be selected based on the purpose for which they were developed.