DOE manages the disposal of cleanup wastes that come from remediation, decontamination, and demolition at sites where operations have been discontinued. Cleanup wastes are primarily subject to three laws: the Atomic Energy Act of 1954, as amended; the Resource Conservation and Recovery Act of 1976 as amended (RCRA); and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended (CERCLA). DOE is responsible for the management of its own radioactive wastes under the Atomic Energy Act. Under RCRA, the Environmental Protection Agency (EPA) or states with programs authorized by EPA regulate the hazardous components of mixed wastes. The Congress enacted CERCLA to clean up the nation’s most severely contaminated hazardous waste sites. Under CERCLA, which is administered by EPA, the parties responsible for the contamination are responsible for conducting or paying for the cleanup. The statute makes federal facilities subject to the same cleanup requirements as private industry. For CERCLA projects, EPA has established a decision process designed to involve the public and EPA in identifying, evaluating, and choosing cleanup approaches. This process requires parties responsible for the cleanup (in this case DOE) to consider a range of cleanup alternatives. EPA uses nine specific criteria, including the estimated costs, feasibility, and risks for each alternative, to evaluate, compare, and balance tradeoffs among these alternatives (see fig. 1). Under these criteria, any selected cleanup alternative must adequately reduce long-term risks to human health and the environment. The chosen alternative—including the plan for disposing of the waste—is documented in a Record of Decision (ROD), which EPA must approve. Officials at the three sites we reviewed considered detailed estimates of the costs and risks associated with on-site and off-site waste disposal. Among other things, these estimates were based on preliminary determinations on the extent and type of contamination present at the site. In accordance with the CERCLA decision process, site officials also assessed how well each cleanup alternative addressed the nine CERCLA criteria. After balancing the tradeoffs among the criteria for each alternative, site officials selected an on-site disposal alternative based, at least in part, on their estimation that on-site disposal would cost less than off-site disposal (see table 1). To meet the CERCLA requirement that human health and the environment be adequately protected, DOE sites adopted accepted strategies, such as limiting the level of contamination allowed in the disposal facility, to mitigate long-term risks. DOE, EPA, and other stakeholders agreed that the benefits of on-site disposal, including cost savings, outweighed the remaining long-term risks. In accordance with the first steps in EPA’s CERCLA decision process, all three sites conducted remedial investigations to confirm and to quantify the nature and extent of contamination. They examined site background and historical data, and used limited sampling to project the volumes and types of wastes that could be generated by cleanup activities. Based on this limited information, officials at each site developed a preliminary model describing the sources of contamination (such as soil or groundwater), possible ways the contaminants could be released, and whether human exposure would be likely. Using this model, they assessed the cancer and non-cancer risks to humans. Officials at each site also prepared a feasibility study that established cleanup goals, identified possible cleanup technologies and actions, and analyzed alternative cleanup approaches. For the contaminants of concern, officials set cleanup goals at contamination levels that posed acceptable risks according to their exposure model. The waste excavation and disposal approach, either on-site or off-site, was only one of many approaches available to officials to meet these cleanup goals. For example, each site considered leaving at least some waste in place and limiting human exposure to it by either capping the waste with clean cover materials or restricting access to the waste areas. Site officials developed their alternative cleanup approaches using the results of their remedial investigations and working closely with EPA and state reviewing officials. Officials in Oak Ridge and Idaho determined that feasible cleanup approaches were likely to generate more waste than the existing disposal facilities at those sites could accommodate, and the Fernald site had no existing disposal facility. Therefore, when conducting their feasibility studies, officials at each of the three sites considered whether to dispose of their respective wastes in a new on-site facility or to ship them to an off- site disposal facility. Specifically, each site used the Envirocare facility in Utah as its representative off-site disposal facility. DOE and commercial generators of radioactive waste use this facility, which is located 80 miles west of Salt Lake City, to dispose of mildly contaminated soils and debris. In addition to the Envirocare facility, DOE sites that do not have existing on-site disposal facilities are now authorized to dispose of their low-level and mixed low-level wastes at DOE’s disposal facilities for these types of wastes at its Hanford Reservation in southeastern Washington and its Nevada Test Site in southern Nevada. Site officials assessed each proposed cleanup alternative against the cleanup goals, as well as nine decision criteria specified in EPA’s CERCLA regulations and guidance. Following this guidance step-by-step, officials first considered the two threshold criteria, then evaluated qualifying alternatives against the five balancing criteria, and then applied the two modifying criteria. CERCLA threshold criteria require a cleanup approach to (1) achieve overall protection of human health and the environment and (2) meet all legal requirements, referred to as “applicable or relevant and appropriate requirements.” Site officials discarded some alternatives, such as capping some contaminated areas in place, because they did not meet these threshold criteria. In some instances, waivers were needed to develop on-site disposal facilities. For example, the Fernald site obtained a waiver from the state of Ohio’s prohibition on developing a disposal facility over a drinking water aquifer. Similarly, the Oak Ridge site obtained a waiver from EPA‘s minimum required distance from the bottom of a landfill that contained toxic chemicals to the underlying groundwater. Without these waivers, the sites would not have been able to develop on- site disposal facilities. (See appendix I.) In both instances, the host states and EPA agreed with site officials that the proposed facilities could be designed to meet equivalent safety standards. After screening cleanup alternatives against the two threshold criteria, site officials developed more detailed feasibility studies to demonstrate how well the various surviving alternatives met each of five CERCLA balancing criteria. The sites used measures that employed varying degrees of data and subjectivity to evaluate how effectively an alternative met each criterion (see table 2). All three sites then used these evaluations to balance the criteria for on- site and off-site disposal alternatives. Generally, each alternative approach had strengths and weaknesses in some of the criteria, and the sites had to make tradeoffs according to their unique conditions and priorities. Table 3 lists the key tradeoffs each site cited in its comparative analysis between on-site and off-site alternatives of similar cleanup scope. (See appendix 1 for a description of each site’s comparative analysis.) Officials at each site applied the two CERCLA modifying criteria—state and community acceptance—to its preferred alternative of on-site disposal for most of its waste. Each site involved state and community stakeholders early in the decision process. State environmental agencies participated in preliminary reviews and informal discussions from the start of the Remedial Investigation throughout the final cleanup decision. Generally, by the time site officials issued their Final Record of Decision, they had addressed, or had a plan to address, environmental concerns raised by the states. For example, the Ohio Environmental Protection Agency supported the development of an on-site facility in Fernald contingent upon specific restrictions on the source of and radioactivity in any waste accepted for disposal. The Record of Decision incorporated an approach to meet these restrictions. Site officials also involved and informed community stakeholders, and received support for their decisions from groups such as the Fernald Citizens Task Force, the Oak Ridge Reservation Environmental Management Site Specific Advisory Board, and the INEEL Citizens Advisory Board. The Fernald Citizens Task Force, which is comprised of individuals with diverse interests in the future of the site, convened in 1993 to provide focused input on central cleanup issues at Fernald. A Task Force report issued in 1995 included recommendations on the site’s future use, waste disposal options, and cleanup objectives and priorities. DOE’s selected alternative mirrored these recommendations. All three sites held public hearings on their Proposed Plan and ROD, and accepted comments for the time periods required under CERCLA. The resulting comments and DOE responses were incorporated in the decision documents. In each case, host state environmental agencies concurred with the proposed decisions. Each DOE site and its respective EPA region then signed a Final ROD that documented the decision for an on-site disposal facility. This final decision allowed DOE sites to move forward with planning for site excavation and construction. After deciding to build new on-site disposal facilities, site officials continued to refine disposal needs and develop specific plans for these facilities for one or more years. During this time, significant changes occurred in site assumptions regarding the types and volume of wastes needing disposal, detailed design of on-site facilities, duration of the cleanup, and cost of off-site transportation and disposal. Under such circumstances, good business practice suggests that earlier cost estimates should be confirmed before construction begins. Likewise, 1997 guidance issued by the Office of Management and Budget (OMB) states that agencies should validate their earlier planning decisions with updated information before finalizing capital investments. However, the three sites conducted little further evaluation of off-site disposal options, despite changed circumstances that could narrow the cost difference between on- site and off-site disposal. At Oak Ridge, for example, a simple update of the projected waste volumes, transportation rates, and costs for off-site disposal of some types of waste effectively reduced the difference between on-site and off-site cost estimates by 51 percent.