Significant risk decisions in federal regulatory agencies.

The completion of a risk assessment does not reveal whether the assessed risk is of significant public health importance. Little attention has been paid to the development of rigorous analytic approaches to the determination of risk significance. This paper reviews a number of major FDA, EPA, and OSHA decisions regarding significant carcinogenic risks and identifies several problems that need to be explored more fully to ensure that both the qualitative and quantitative features of a risk assessment are considered in the determination of risk significance.