Summary: After 12 years and more than $15 billion spent on the Superfund program, questions remain about the Environmental Protection Agency's (EPA) progress in cleaning up hazardous waste sites. EPA has placed 1,275 sites with the most serious problems on a cleanup priority list. EPA has evaluated the potential risks of many of these sites and is now cleaning up 374 of them. This report (1) discusses EPA's efforts to conduct cleanups, including the type and extent of cleanup work at sites deleted from the priority list or sites where cleanup construction is complete, and (2) evaluates the challenges that EPA will face in managing and monitoring these sites. GAO summarized this report in testimony before Congress; see: Superfund: Cleanups Nearing Completion, Future Challenges, and Possible Cleanup Approaches, by Peter F. Guerrero, Associate Director for Environmental Protection Issues, before the Subcommittee on Superfund, Recycling, and Solid Waste Management, Senate Committee on Environment and Public Works. GAO/T-RCED-93-69, Sept. 9, 1993 (24 pages).