Quantitative Risk Assessment and Cost-Benefit Analysis for Carcinogens at EPA: A Critique

Abstract

A review of risk assessment at the Environmental Protection Agency (EPA) points out the serious lack of toxicological testing data for commercial chemicals and pesticides as well as a disturbing trend toward undue reliance on quantitative risk assessment (QRA) and cost-benefit analysis (CBA). The apparent precision of quantitative estimates of risk masks the many underlying value judgments and uncertainties. In an attempt to address the uncertainties in QRA, EPA has recently published Guidelines on Risk Assessment for Carcinogens. The Guidelines are generally sound; however, they do not address human variability in response and possible synergistic interactions which can lead in some cases to an underestimate of risk. Moreover, they offer a simplistic carcinogen classification scheme which has already been misused to justify less stringent regulation of waterborne carcinogens. Since 1982, EPA's ever greater use of QRA coupled to CBA has led to relaxed standards or decisions not to regulate certain sources of environmental pollutants such as benzene and radionuclides. Risk managers should not be seduced by the precision of the numbers into using QRA and CBA as the primary tool in setting public health policy. When estimated risk is inserted into a cost-benefit analysis under “benefits” or cancers avoided, its own uncertainties are compounded by those regarding the true economic impacts of the regulation.