Expert Report

Best Practices for Risk-Informed Decision Making Regarding Contaminated Sites: Summary of a Workshop Series (2014)

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During the Second World War and the ensuing Cold War, the United States created a massive industrial complex to produce nuclear materials and weapons for national defense. The activities also produced large quantities of radioactive and hazardous wastes that resulted in widespread groundwater and soil contamination. In 1989, the Office of Environmental Management (EM) was created within the Department of Energy, with the mission of the safe cleanup of sites associated with the government-led development of nuclear weapons and nuclear energy. Currently, cleanup operations are proceeding under legally enforceable agreements with timelines for hundreds of milestones. EM is reviewing alternative approaches to decision making that may increase effectiveness and improve the cost-efficiency of its cleanup activities, especially for sites that will have residual contamination when active cleanup is complete.

To inform this review, EM asked the National Research Council to convene two workshops to examine best practices for risk-informed remedy selection, closure, and post-closure control of radioactive and chemically contaminated sites that cannot be remediated for unrestricted release. The workshops, held in October 2013 and January 2014, brought together federal and state agency decision makers responsible for contaminated site cleanup and closure decisions, federal and state regulators, key stakeholders, and other technical experts to present remediation challenges and case studies. This report combines summaries from each workshop, including factual descriptions of presentations and discussions, and a short, introductory overview section that outlines the major themes that emerged, including decision-making processes, regulations and flexibility, models and timeframes, communication among stakeholders, and weighing environmental resources in decisions.