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Risk Assessment

Risk Characterization Handbook

This Handbook was prepared by the Science Policy Council (SPC) for EPA staff and managers and others as a guide to Risk Characterization. It implements EPA’s March 1995 Risk Characterization Policy which improved on the foundation of the February 1992 Agency-wide policy for risk characterization. Both the 1992 and 1995 documents point out that “... scientific uncertainty is a fact of life (and) ... a balanced discussion of reliable conclusions and related uncertainties enhances, rather than detracts, from the overall credibility of each assessment …”. Both also note that while the role of science to inform but not make decisions is widely recognized in EPA, and in the larger risk assessment and regulatory community, these communities often use the risk assessment number as the stated reason for decisions, not always clearly highlighting the legal, economic, social and other non-scientific issues that also go into the decision.

From the start it was recognized that implementation of this policy would require a culture change at EPA and that achieving an Agency-wide culture change would not be effective if imposed from the top down. Thus, every effort was made to engage career EPA employees, including risk assessors, risk managers and senior decision-makers across the Agency to help implement the policy. The effort was monumental, directly involving several hundred Agency employees in all Offices and Regions. A Risk Characterization Implementation Team was established with members from each Region and Program Office, including the Office of General Counsel, to guide and direct the initial efforts to implement the policy.

Note: This Handbook has two parts. The first is the Risk Characterization guidance itself. The second part comprises the Appendices which contain the Risk Characterization Policy, the risk characterization case studies and references.

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