Method for estimating the human and environmental exposure potential of chemicals having designated uses

This paper describes a methodology that was designed to assist the Environmental Protection Agency in setting priorities for regulating chemicals in accordance with requirements of the Toxic Substances Control Act by indicating the extent of exposure potentially associated with a particular use of a chemical. Development and application of the methodology to actual chemical uses proceeded in four stages: (1) development of an exposure classification scheme, (2) development of a chemical use list, (3) assignment of exposure category scores to chemical uses, and (4) merging of exposure scores into ranked groups, creating the Index of Exposure. The purpose of the Index was to identify those chemical uses having the greatest potential for human and environmental exposure. Theoretically, the objectivity of the scoring methodology is such that, given the same data for a chemical use, different scorers will be able to arrive at the same exposure score for that use.