How Clean is Clean?: A Comparative Analysis of the Reliance of RiskAssessment in Contaminated Site Cleanup

Quantitative risk assessment is a crucial tool indetermining the degree of clean up at contaminatedsites and to answer the fundamental question -- how cleanis clean? The purpose of this study was to examinehow the U.S. Environmental Protection Agency hasrelied on quantitative risk assessment in its threesite remediation programs: Superfund, the RCRACorrective Action Program, and the UndergroundStorage Tank Corrective Action Program. Interestingly, each of these programs were createdwithin a few years of each other, has the samestatutory cleanup goals, addresses some similarcontaminants, addresses the same environmental media,uses the same toxicological data, and uses the samedefault exposure assumptions. However, over time,each program's reliance has become quite different.This study explores the scientific, political,programmatic, organizational, historical, andsocio-economic factors that have influenced thedivergence.