In 1980, the Congress passed the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), which established the Superfund program to clean up highly contaminated hazardous waste sites. EPA administers the program, oversees cleanups performed by the parties responsible for contaminating the sites, and performs cleanups itself. State governments also have a role in the Superfund process. States may enter into contracts or cooperative agreements with EPA to carry out certain Superfund actions, including evaluating sites, cleaning them up, and overseeing the cleanups. In addition, most states have established their own hazardous waste programs that can clean up sites independently of the federal Superfund program. State cleanup programs include efforts to enforce state cleanup laws on responsible parties and to encourage them to “voluntarily” clean up contaminated sites. CERCLA requires EPA to develop and maintain a list of hazardous sites, known as the National Priorities List, that the agency considers to present the most serious threats to human health and the environment. These sites represent EPA’s highest priorities for cleanup nationwide. Although EPA may undertake cleanup actions at contaminated sites not on the National Priorities List, the agency’s regulations stipulate that only sites placed on the list are eligible for long-term cleanup (“remedial action”) financed by the agency under the trust fund established by CERCLA. Additional details on EPA’s process for placing sites on the National Priorities List are included in appendix I. The 3,036 sites that were awaiting a National Priorities List decision as of October 1997 represent only a portion of the sites that EPA has evaluated and classified over the history of the Superfund program. According to EPA, as of November 1998, the Superfund program had investigated over 40,000 potential hazardous waste sites and made final decisions about whether or not to include almost 35,000 sites on the National Priorities List. EPA also reported that it has removed waste or taken other interim cleanup actions at over 5,500 sites—most of which are not on the National Priorities List—to address the most urgent risks and stabilize conditions to prevent further releases of contamination. For the more than 1,400 sites EPA has placed on the list, it has completed cleanup studies at most and has completed cleanup construction at 585. States have reported cleaning up thousands of sites under their own programs and authorities. To obtain information on the 3,036 sites that EPA identified as awaiting a National Priorities List decision, we developed and mailed two surveys for each nonfederal site and three surveys for each federal facility. We sent surveys to site assessment officials in EPA’s 10 regional offices, and since state officials might have more knowledge of some of the sites, we also sent surveys to the 50 states, the District of Columbia, Guam, Midway Island, the Northern Mariana Islands, Puerto Rico, and the Navajo Nation (collectively referred to as states in this report). In addition, if a federal agency is responsible for cleaning up sites, we also sent surveys to that agency: We surveyed 14 federal agencies for 157 of the 3,036 sites that are federally owned and/or operated. Because we did not receive responses from some states and incomplete responses from others, we sent follow-up surveys to state officials. In total, we received one or more survey responses for 3,023 (99.5 percent) of the 3,036 sites identified by EPA as awaiting a National Priorities List decision. We discuss our methodology in greater detail in appendix II, and appendix III includes reproductions of our surveys. The responses to our surveys of officials of EPA, other federal agencies, and states indicate that 1,789 of the 3,036 sites classified by EPA’s database as awaiting a National Priorities List decision are potentially eligible for the list. Another 1,234 sites are unlikely to become eligible for the Superfund program for various reasons. First, EPA’s database of potentially contaminated sites, known as the Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS), inaccurately lists some sites as awaiting a National Priorities List decision although they are not eligible for listing. EPA regions reported that about 19 percent of the 3,036 sites should not be considered eligible sites because (1) they received preliminary hazard ranking scores below the qualifying level or (2) EPA has already proposed them for the list or decided not to propose them for the list. According to an EPA Superfund program official, the incorrect data entries may have resulted from regional program managers’ misinterpretation of EPA’s guidance on CERCLIS coding. We consider another 22 percent of the sites unlikely to become eligible for the National Priorities List because, according to responding officials, they either do not require any cleanup action (183 sites), have already been cleaned up (182 sites), or are currently undergoing final cleanup (304 sites) under state programs. No information is available on the status of the remaining 13 sites because of missing survey responses (see fig. 1). Final cleanup under way (304 sites) Sites potentially eligible for the NPL (1,789 sites) We performed most of our analysis of site conditions, cleanup activities, and plans for future cleanups for the 1,789 sites remaining after we excluded the categories of sites that are shaded in the figure. We refer to the remaining sites as potentially eligible sites. They include 1,739 nonfederal sites and 50 federal facilities. Responses to our surveys indicate that many of the 1,789 sites that are potentially eligible for the National Priorities List pose risks to human health or the environment. Most of them threaten drinking water sources or groundwater; they are generally located in populated areas; and although many of the sites are fenced to prevent entry, workers, visitors, and trespassers may have direct contact with contaminants at more than half of the sites. The sites are contaminated most often with metals, but other contaminants are also present. Officials of EPA, other federal agencies, and states who responded to our survey characterized the risks presented by about two-thirds of the potentially eligible sites. They said that about 17 percent of the sites currently pose high human health and environmental risks; another 10 percent of the sites potentially pose high future risks. In addition, officials were unsure about the severity of site conditions for a large proportion of potentially eligible sites. A large portion of the potentially eligible sites have contaminated nearby groundwater, drinking water sources, or both. As figures 2 and 3 indicate, about 73 percent of the potentially eligible sites have already contaminated groundwater, and another 22 percent of the sites, approximately, could contaminate groundwater in the future. In addition, about 32 percent of the potentially eligible sites have already contaminated drinking water sources, and about 56 percent more could contaminate drinking water sources in the future. Actual groundwater contamination (1,301 sites) The contamination at many of the potentially eligible sites is also resulting in a number of other adverse conditions. Table 1 shows the percentage of potentially eligible sites that have experienced or contributed to specific conditions. As the table also shows, respondents to our surveys were uncertain whether the conditions were present at a relatively large percentage of the potentially eligible sites. As figure 4 shows, the sites that are potentially eligible for the National Priorities List are contaminated by a variety of pollutants. Metals—primarily heavy metals such as lead, mercury, or cadmium—are the principal contaminants at these sites. These metals can cause brain and kidney damage and birth defects. The second most prominent contaminants at these sites are volatile organic compounds (VOC). VOCs are carbon-based compounds, such as benzene, that easily become vapors or gases and can cause cancer, as well as damage to the blood, immune, and reproductive systems. A large portion of the potentially eligible sites are also contaminated by semivolatile organic compounds (SVOC), which are similar to VOCs and can result in human respiratory illnesses. Additional major contaminants at the sites are pesticides, the most toxic of which can cause acute nervous system effects and skin irritations and may cause reproductive system effects and cancer; polychlorinated biphenyls (PCB), which can cause skin irritations and other related conditions and may contribute to causing cancers, liver damage, and reproductive and developmental effects; dioxins, which are also a suspected human carcinogen; and other unspecified contaminants. The potentially eligible sites are generally located in populated areas: Ninety-six percent are within a half mile of residences or places of regular employment. We asked officials of EPA, other federal agencies, and states to rank the relative risks of potentially eligible sites. The officials responding to our surveys said that they could assess the current risks of 67 percent of the sites and the potential risks of 68 percent of the sites. According to these officials, about 17 percent of the potentially eligible sites currently pose high risks (see fig. 5), and another 10 percent of the sites (for a total of 27 percent) could pose high risks in the future (see fig. 6) if they are not cleaned up. Average current risks (455 sites) Low current risks (443 sites) The 1,789 sites that are potentially eligible for the National Priorities List include (1) 686 sites where some cleanup activities have reportedly taken place or are currently being conducted but the final cleanup remedies are not yet under way and (2) 1,103 sites where officials reported that no substantive cleanup activities beyond initial site assessments or investigations have occurred or no information on cleanup progress is available. Data on the year in which each potentially eligible site was entered into EPA’s records—the “discovery date”—indicate that a significant portion of these sites have been in EPA’s and states’ inventories of known hazardous waste sites for more than a decade. Furthermore, 45 percent of the sites reported to have high current risks and 47 percent of the sites with high potential risks have not had any cleanup activities, or no information on their cleanup progress is available.