When the Congress passed the Comprehensive Environmental Response and Compensation Act (CERCLA), commonly known as the Superfund law, in 1980, it established a trust fund (Superfund), financed primarily by taxes on crude oil and certain chemicals, for cleaning up highly contaminated hazardous waste sites. It also required EPA to develop a list of priorities for cleaning up the most hazardous waste sites, called the National Priorities List (NPL). In 1986, the Congress reauthorized Superfund and required EPA to meet certain cleanup schedules and to give preference to methods that permanently decontaminate sites. In 1990, the Congress again reauthorized Superfund, adding $5.1 billion to the program. In total, $15.2 billion has been authorized for the program. As of September 30, 1995, EPA had listed or proposed to list about 1,290 sites on the NPL, completed construction at about 304 sites, and deleted 84 sites from the list. The agency estimates that the average cost of cleaning up an NPL site, to the federal government or responsible parties, is $26 million. The Senate bill contains numerous provisions designed to address cleanup costs. We would now like to discuss some of the implications of the bill’s provisions. Several provisions in S. 1285 would elevate the role of risk and site-specific risk assessments in decisions about whether and how extensively a site should be cleaned up. We have reported that basing these decisions on environmental standards and generic assumptions about such things as the projected future use of a site, rather than actual data from the site, can lead to extensive and costly cleanups. EPA has recently introduced reforms to resolve some of these issues, but S. 1285 would take more extensive measures. One criticism of the current Superfund law is that it has resulted in some cleanups that were more extensive and costlier than were warranted by the health risks at sites. Such results may occur, in part, because the 1986 Superfund amendments require that cleanups comply with all “applicable” or “relevant and appropriate” standards set in other federal and state environmental laws, including certain standards set under the Safe Drinking Water Act and the Clean Water Act where relevant and appropriate. The Senate bill would require compliance only with “applicable” standards, that is, with those that directly pertain to hazardous waste cleanups, and it would eliminate the reference to the specific acts. The bill would also provide opportunities for the states to define their own applicable standards. The proposed legislation would allow EPA to waive the standards if reaching them, among other things, is technically infeasible or unreasonably costly. The extent to which this change affects cleanups will depend, in large part, on whether states establish their own cleanup standards and whether these standards differ significantly from those that have been used at cleanups to date. In a recent survey of states, we found that 21 of the 33 states we contacted had already set standards for groundwater or soil cleanups, or for both types, that specify numeric limits on acceptable concentrations of chemicals. Additionally, some states have general policies about cleanup, such as requirements that chemicals be limited to the levels that occur naturally in the immediate environment. For groundwater, 20 of the states had set numeric standards that were similar to the federal drinking water standards, although most of these states had set more stringent standards for a few chemicals. For soil, which has few federal standards, 13 of the 20 states had set their own cleanup standards. We did find, however, that the states were flexible in allowing exceptions to the cleanup levels required under the standards in order to account for conditions making it difficult or unnecessary to reach the standards. In states that have not established their own standards, site-specific risk assessments would play a more important role in determining the extent of Superfund cleanups. When we reviewed EPA’s data for 225 Superfund sites, we found that having used risk assessments instead of standards to determine the need for cleanups would not significantly have changed the number of sites cleaned up but would sometimes have changed the extent of the cleanups. To comply with the law, EPA had used federal and state standards rather than risk assessments to determine the extent of the cleanups at about three-fourths of the 139 sites in the database for which information on the basis for cleanup was available. If EPA had relied more on risk assessments, as S. 1285 would require, some of these cleanups might have been less extensive—and less expensive. This is because, as EPA program officials acknowledged, standards tend to require more stringent cleanups than risk assessments. Using risk assessments to determine cleanup levels without changing the risk assessment process itself could still result in more extensive cleanups than might be warranted at some sites. When EPA lacks specific data about a site, it makes assumptions in its estimates of risk about both the quantity of contaminants that will reach people and the toxicity of these contaminants. EPA tends to make relatively conservative assumptions, justifying this tendency on the basis that it has a mandate from the Congress to protect all individuals around Superfund sites. Critics argue that these assumptions are not realistic for all sites. The Senate proposal calls for the use of site-specific data and “realistic and plausible” assumptions about the risks posed by contaminants. For example, the bill calls for considering data about a site when deciding how the land at a site may be used in the future. Determining a site’s future use is key to estimating people’s future exposure to contaminants at the site, which, in turn, helps to determine the level of cleanup required for the site. We found that when EPA lacked specific data on a site’s future use, it adopted the assumptions that would be the most protective of human health, namely, that the land would be used for residential rather than commercial or industrial purposes. Assuming future residential use can lead to estimates of health risks that warrant cleaning up a site immediately. In reviewing EPA’s data for 225 Superfund sites, we found that at about half of the 190 sites where EPA had decided cleanup was necessary, the health risks were ranked as high not because of the land’s current use but because EPA had assumed the land’s use would change in the future. EPA recognizes that this assumption leads to costlier cleanups, and last year the agency decided to use more site-specific data when deciding what assumptions to make about a site’s future uses. The proposed legislation would go farther to incorporate the assumptions about future land use in cleanup decisions. Given that both the government and private industry have spent billions of dollars to date on the Superfund program but significant numbers of sites remain to be cleaned up, it is important to achieve the maximum amount of environmental protection from the available federal resources. We reported in 1994 that although EPA had adopted a policy of addressing the worst sites first, its regional offices had set priorities using such factors as the amount of work needed to evaluate a site instead of considering the site’s health and environmental risks. Recently, in response to expected budget reductions, EPA convened a panel to help rank NPL sites nationwide on the basis of risk and other factors. In the past, EPA has taken similar actions when resources have been limited, but its efforts have been short-term. We have also reported that national risk-based priority-setting systems have not been fully implemented at the Departments of Defense and Energy. Of the hundreds of federally owned hazardous waste sites, only eight have been cleaned up so far. Although most of the work remains to be done, agencies’ budgets for the federal cleanup and compliance effort, whose costs may ultimately total $400 billion, have been declining. By basing cleanup priorities largely on the relative risks of sites, agencies could ensure that funds are effectively allocated. Both the Congress and EPA are concerned about the high costs of cleanups and are trying to curb these costs. The current law’s requirements that cleanup remedies comply with federal and state environmental standards and permanently treat waste have limited the alternatives available to cut costs. EPA now plans to review any remedies that exceed certain cost thresholds to determine whether lower-cost alternatives are available. The agency is also evaluating the results of a 1992 initiative that uses EPA’s emergency response, or removal, authority to clean up portions of sites more quickly and at less cost. The Senate bill would also address costs by eliminating the preference for permanent treatments of waste, thereby allowing for greater consideration of remedies that rely on the containment of waste than exists under current law. The bill would also increase the current law’s dollar and time limits on federally funded removals. These changes would facilitate EPA’s use, where appropriate, of removal actions, which are faster and less costly than EPA’s traditional cleanup processes. After the 1986 amendments to CERCLA established a preference for permanently treating wastes, EPA increasingly selected permanent measures, such as incinerating contaminated soil, rather than containment measures, such as fencing it off from human contact. This preference, in turn, increased shorter-term cleanup costs because constructing treatment technologies is more expensive than installing containment measures. Currently, about half of all cleanup plans include permanent treatments. The bill would eliminate the preference for permanence, thereby allowing the expanded use of containment options. Such options include implementing lower-cost engineering controls (like waterproof covers to contain rather than clean up waste) and institutional controls (like land-use restrictions), as long as they protect human health and the environment. However, while the costs to implement these remedies might be lower, they would require long-term monitoring and maintenance to ensure that they remain protective. We estimate that the average cost of operating and maintaining a site with contained waste could be $5 million over 30 years. We also estimate that during this period, overall operation and maintenance costs to the federal government, states, and responsible parties could be $5 billion, $8 billion, and $18 billion, respectively. We recently reported EPA had identified several sites where alternatives to treatment had been used and problems had developed, requiring additional work.