Pursuant to a congressional request, GAO reviewed how priorities are being set for hazardous waste cleanups, focusing on: (1) whether the Superfund program is identifying the highest-priority cleanup sites; and (2) the Department of Defense (DOD), Department of Energy (DOE), and the Department of the Interior approaches for ranking risks and prioritizing sites for cleanup.

GAO found that: (1) the Superfund program does not completely and consistently identify the federal facilities presenting the greatest risks to public health and the environment; (2) without a complete inventory of contaminated sites, adequate data on the risks at these sites, and consistent policy guidance, agencies cannot fully prioritize cleanup activities; (3) the National Priorities List (NPL) does not include all eligible contaminated sites and the Hazard Ranking System does not provide sufficient information to rank contaminated facilities on the basis of risk; (4) federal agencies responsible for cleanups do not use a consistent approach to assess relative risk; (5) to help set cleanup priorities and make funding decisions, DOD developed a risk-ranking tool to categorize contaminated sites; (6) DOE uses a qualitative, facility-based approach to evaluate contaminated sites and prioritize cleanups; (7) Interior uses a centralized priority-setting mechanism in the later stages of the Superfund process to rank its contaminated facilities; and (8) while individual agencies use their own risk-assessment processes, it would be more cost-effective for agencies to use a consistent, national approach to rank risks and identify high-priority sites.