This section discusses EPA’s process for assessing sites under the Superfund program and the approaches identified by EPA for conducting long-term cleanups at sites eligible for the NPL under the Superfund program and under other available approaches. Under the Superfund program, EPA assesses hazardous waste sites for long-term cleanups through a specific process. At some point after a potential hazardous waste site is reported to the Superfund program and entered into CERCLIS, EPA regional officials, their contractors, or states acting under cooperative agreements with EPA evaluate the relative potential for a site to pose a threat to human health and the environment. EPA’s 10 regional offices each are responsible for implementing Superfund within several states and, in some cases, territories. Under CERCLA, EPA may only pay for a remedial action at a site if the relevant state agrees, among other things, to pay a portion of the cleanup expenses, as well as all operations and maintenance costs. In addition, under a cooperative agreement with EPA, a state may assume the lead oversight role at a site in the Superfund program. Figure 1 shows the states included in each of the 10 EPA regions. During the initial phases of the long-term cleanup process—known as preliminary assessment and site inspection—EPA regional officials or their counterparts evaluate the potential need for additional investigation or action in connection with a release of hazardous substances from a site. Specifically, the preliminary assessment phase involves an evaluation of readily available information about a site and its surrounding area to determine if the release or potential release poses enough of a threat to human health and the environment that further investigation is needed. If further investigation is needed, a site inspection is performed. During this phase, investigators typically collect environmental and waste samples to determine what hazardous substances are present. Information collected during the preliminary assessment and site inspection is used to calculate and document a site’s preliminary Hazard Ranking System score, which indicates a site’s relative threat to human health and the environment based on potential pathways of Sites with a Hazard Ranking System score of 28.50 or contamination.greater are eligible for listing on the NPL. Information collected from the initial assessment phases to develop Hazard Ranking System scores is not intended to be sufficient to determine either the extent of contamination or how to clean up a particular site. After a site is determined to be eligible for the NPL, EPA chooses which long-term cleanup approach is best suited to the site. In some cases, EPA may conduct a short-term cleanup known as a removal action or otherwise delay selection of a long-term cleanup approach. EPA may choose among several approaches to address sites with a relative threat to human health and the environment that is sufficiently severe to make them eligible for listing on the NPL. For long-term cleanups, EPA can retain oversight of sites under the Superfund program or defer the oversight of sites to other approaches, as shown in figure 2. Under its Superfund program, EPA conducts long-term cleanups using three approaches. The first and most common approach under the Superfund program involves listing a site on the NPL. To do so, EPA first proposes the site for listing on the NPL in the Federal Register. EPA then accepts public comments on the proposal and responds to the comments in a second and final Federal Register listing announcement of the site; then the agency may place on the NPL those sites that continue to meet the requirements for listing. The second approach that EPA may use under the Superfund program is the SA approach, which began informally in the 1990s whereby some EPA regions negotiated site cleanup agreements with PRPs for sites that PRPs, states, or local government officials and communities did not want to have listed on the NPL. To promote consistency across regions, EPA issued guidance in 2002 formalizing the SA approach, which it subsequently updated in 2004 and 2012. According to EPA’s guidance, to qualify for the SA approach, (1) a site’s contamination must make it eligible for listing on the NPL; (2) EPA must anticipate a long-term cleanup at the site; and (3) there must be a willing, capable PRP who will negotiate and sign an agreement with EPA to perform the investigation or cleanup. The third approach EPA can use for long-term cleanup of sites is to address sites under the Superfund program but not list them on the NPL or address them through the SA These “Other” sites under the Superfund program can vary approach.widely and include, among others, some sites with cleanup agreements that preceded the SA approach. Under these older agreements, for which there was no guidance at the time they were negotiated, EPA agreed not to list the site on the NPL, and the PRPs agreed to conduct the cleanup, according to EPA officials. Irrespective of the approach chosen, all sites under the Superfund program approaches follow the same general phases for long-term cleanup, as shown in figure 3, and EPA officials oversee the cleanup at all of these Superfund sites. After the initial phases of the long-term cleanup process, EPA or a PRP conducts a two-part study of the site: (1) a remedial investigation to further characterize site conditions and assess the risks to human health and the environment, among other actions, and (2) a feasibility study to evaluate various cleanup options to address the problems identified in the remedial investigation. At the conclusion of these studies, EPA selects a remedy for addressing the site’s contamination and develops a cost estimate for implementing the remedy; both of these are included in a record of decision. According to EPA officials, the level of cleanup depends on site-specific conditions, not the particular approach selected. EPA or a PRP then develops the method of implementation for the selected remedy during the remedial design phase and implements it during the remedial action phase, when actual cleanup of the site occurs. Multiple cleanup activities can occur within a given phase at the same or different operable units at one site. For example, one remedial action at an operable unit may address soil contamination, while another remedial action at the same operable unit may address groundwater contamination. When EPA or a PRP finishes the cleanup remedy at a site, all immediate threats have been addressed, and all long-term threats are under control, EPA generally considers the site to be “construction complete.” For sites listed on the NPL, when EPA, in consultation with the state, determines that no further site response is appropriate, the agency may delete the site from the NPL. EPA reports achievements at NPL sites, including completion of some phases of the cleanup process, as part of the agency’s implementation of provisions under the Government Performance and Results Act of 1993 (GPRA). The act requires federal agencies to develop strategic plans with outcome oriented agency goals and objectives, performance measures to track the progress made toward achieving goals, annual goals linked to achieving the long-term goals, and annual reports on the results achieved. EPA does not report publicly the same achievements for sites that are not on the NPL. CERCLA § 122(a), 42 U.S.C. § 9622(a) (2012). Department of Justice in seeking an injunction to require PRPs to conduct cleanup. Pub. L. No. 94–580, 90 Stat. 2795 (1976) (codified as amended at 42 U.S.C. §§6901- 6992k (2012)). Although RCRA amended the Solid Waste Disposal Act, Pub. L. No. 89– 272, Title II, 79 Stat. 997 (1965), the amended law is nonetheless sometimes referred to as RCRA, a convention we follow here. Subtitle C of RCRA, 42 U.S.C. ch. 82, subch. III (§§ 6921-6939f), governs hazardous waste management. Hereinafter, references are to RCRA as amended. formal state deferral approach, the EPA region still negotiates the level of oversight appropriate for the particular site. EPA may also defer oversight of the long-term cleanup of a site eligible for the NPL through the Other Cleanup Activity (OCA) approach. OCA deferrals go to one of four types of entities (described below): states, federal agencies, tribes, or private parties. OCA deferral to a state places a site under that particular state’s environmental regulations, as opposed to CERCLA authorities. In contrast to formal state deferrals, the OCA deferral to a state involves no formal EPA oversight other than periodic discussions between EPA regional officials and state officials. Since 2012, EPA guidance has indicated regions should have these discussions. OCA deferral to federal agencies places a site under that particular federal agency’s oversight and authorities, according to EPA. Certain federal agencies, such as the Department of Defense, have responsibility and authority for some or all cleanups at their facilities. EPA assigns a status of “Other Cleanup Activity: Federal Facility Lead” to federal facilities that EPA tracks in its CERCLIS database and are being cleaned up outside of the NPL approach (these sites are eligible for listing but are not listed on the NPL). EPA periodically checks in with other federal agencies on the status of cleanup work at these sites. OCA deferral to a tribe places the site under that tribe’s environmental regulations. EPA periodically checks in with tribal regulators on the status of cleanup work at these sites. OCA deferral to private parties applies to certain sites where the cleanup is conducted by a private party. EPA most commonly addresses the cleanup of sites eligible for the NPL by “deferring” oversight to approaches outside of the Superfund program. EPA regions select the cleanup approach and defer oversight of more than half the sites eligible for the NPL to approaches outside of the Superfund program, primarily through OCA deferrals.