Where does risk come from? A story from a small state in upstate New York

1. Where does risk come from?A story from a small state in upstate New York ESPP-78

2. National Research Council, “Red Book” Model of Risk Analysis (1983) ESPP-78

3. Steps in Formal Risk Analysis • Research • Hazard identification • Exposure assessment • Risk characterization • Risk communication • Risk management ESPP-78

4. Analytic Methods for Toxic Chemicals and Their Limitations • Short-term tests (problem: reductionism) • Bioassays (problem: interspecies extrapolation) • choice of test animals • routes of exposure • dose-response issues • Epidemiology (problem:confounding factors) ESPP-78

5. Social Construction of Risk Models • What causal understandings are built into the risk assessment model? • E.g., Cancer begins with a single mutation. • Which parameters are important? • E.g., For cancer causation, what matters is level of exposure, chemical structure, DNA repair. • What measures and methods are used to characterize those parameters? • E.g., structure-activity studies, animal studies, biological uptake from environment ESPP-78

6. Model: From Mouse to Man ESPP-78

7. Biases that may overstate risk • Conservative assumptions in QRA • use of most sensitive species • considering all routes of exposure • use of high-dose testing • Low-dose extrapolation (ignoring possible mechanisms and thresholds) • Tilt toward human-made hazards (e.g., pesticides vs. “natural carcinogens”) ESPP-78

8. Biases that may understate risk • Synergistic effects (multiple exposures) • Vulnerable or non-standard populations • Tilt toward “natural” rather than social or behavioral causes • ignoring behavior as an element of risk • Bias toward “known” scenarios and available evidence ESPP-78

9. Risk Management Strategies • Zero risk (no animal carcinogens in food) • De minimis risk (<10-6 lifetimecancerrisk) • Safety (no observable effect level or NOEL) • Acceptable risk (regulatory standard) • Risk tradeoffs • risks vs. benefits (disease vs. income, speed, connectivity, choice) • risks vs. risks (epidemic vs. drug reaction) ESPP-78

10. Ethical Issues in Risk Analysis • Preventive policy: no “body counts” • No human experimentation • But is it permissible to test low-level exposures on consenting subjects? • Ethical treatment of animals • How conservative should the analyst be? ESPP-78

11. The Analytic-Deliberative model of Risk Analysis ESPP-78