Science and Judgment in Risk Assessment

The public depends on competent risk assessment from the federal government and the scientific community to grapple with the threat of pollution. When risk reports turn out to be overblown--or when risks are overlooked--public skepticism abounds.
This comprehensive and readable book explores how the U.S. Environmental Protection Agency (EPA) can improve its risk assessment practices, with a focus on implementation of the 1990 Clean Air Act Amendments.
With a wealth of detailed information, pertinent examples, and revealing analysis, the volume explores the "default option" and other basic concepts. It offers two views of EPA operations: The first examines how EPA currently assesses exposure to hazardous air pollutants, evaluates the toxicity of a substance, and characterizes the risk to the public.
The second, more holistic, view explores how EPA can improve in several critical areas of risk assessment by focusing on cross-cutting themes and incorporating more scientific judgment.
This comprehensive volume will be important to the EPA and other agencies, risk managers, environmental advocates, scientists, faculty, students, and concerned individuals.

• Front Matter
• Executive Summary
• 1 Introduction
• Part I Current Approaches to Risk Assessment: 2 Risk Assessment and its Social and Regulatory Contexts
• 3 Exposure Assessment
• 4 Assessment of Toxicity
• 5 Risk Characterization
• Part II Strategies for Improving Risk Assessment: 6 Default Options
• 7 Models, Methods, and Data
• 8 Data Needs
• 9 Uncertainty
• 10 Variability
• 11 Aggregation
• Part III Implementation of Findings: 12 Implementation
• References
• Appendix A: Risk Assessment Methodologies: EPA
• Appendix B: EPA Memorandum from Henry Habicht
• Appendix C: Calculation and Modeling of Exposure
• Appendix D: Working Paper for Considering Draft Revisions to the U.S. EPA Guidelines for Cancer Risk Assessment
• Appendix E: Use of Pharmacokinetics to Extrapolate from Animal Data to Humans
• Appendix F: Uncertainty Analysis of Health Risk Estimates
• Appendix G: Improvement in Human Health Risk Assessment Utilizing Site- and Chemical-Specific Information: A Case Study
• Appendix H-1: Some Definitional Concerns About Variability
• Appendix H-2: Individual Susceptibility Factors
• Appendix I: Aggregation
• Appendix J: A Tiered Modeling Approach for Assessing the Risks Due to Sources of Hazardous Air Pollutants
• Appendix K: Science Advisory Board Memorandum on the Integrated Risk Information System and EPA Response
• Appendix L: Development of Data Used in Risk Assessment
• Appendix M: Charge to the Committee
• Appendix N-1: The Case for
• Appendix N-2: Making Full Use of Scientific Information in Risk Assessment
• Index