What to do at low doses: a bounding approach for economic analysis

Area of Science:

• Environmental Science
• Toxicology
• Risk Assessment

Background:

• Environmental policies require health benefit quantification, often using linear extrapolation for carcinogen risk assessment.
• US EPA's 1996 proposed guideline revisions may limit quantitative risk assessment for nonlinear carcinogens.
• This impacts benefit-cost analyses of policies reducing cancer risks.

Purpose of the Study:

• Examine implications of EPA guideline changes on carcinogen exposure benefit-cost analysis.
• Propose an approach for bounding dose-response relationships when biological models are unavailable.
• Enable quantitative estimates of reduced illness for nonlinear carcinogens in risk assessments.

Main Methods:

• Analysis of proposed changes to EPA's 1986 Guidelines for Carcinogen Risk Assessment.
• Development of a bounding approach for dose-response relationships of nonlinear carcinogens.
• Application of the bounding approach to chloroform exposure case study.

Main Results:

• Proposed EPA revisions could hinder benefit-cost analysis by reducing quantitative risk data.
• A bounding approach can estimate dose-response relationships for low-level nonlinear carcinogen exposures.
• The method provides reduced illness estimates for benefit-cost analysis, accounting for nonlinearities.

Conclusions:

• Benefit-cost analysis can be supported even with limited quantitative data for nonlinear carcinogens.
• The proposed bounding approach offers a viable method for estimating health benefits.
• This approach ensures continued economic evaluation of environmental policies reducing cancer risks.