CERCLA, often referred to as the “Superfund” law, gave the federal government the authority to respond to actual and threatened releases of hazardous substances, pollutants, and contaminants that may endanger public health and the environment. EPA established the Superfund program to carry out these responsibilities. Data as of September 2011— the most current data available—show that there were 13,856 sites in EPA’s CERCLIS active site inventory, which may require attention under EPA’s Superfund program. Management of these sites, including the special accounts associated with them, has historically been the responsibility of the EPA region in which a site is located. EPA has 10 regional offices, each one responsible for the execution of EPA programs within several states and, in some regions, territories. Figure 1 shows the states included in each of the 10 regions. This section discusses (1) EPA’s process for cleaning up Superfund sites, (2) EPA’s enforcement process for site cleanup, (3) the Trust Fund established under CERCLA, (4) EPA’s use of special accounts for Superfund cleanup, and (5) the EPA IG’s recommendations for better management of these special accounts. EPA’s Superfund cleanup process can be lengthy, sometimes taking decades to clean up contamination to the standards selected for a site. The cleanup process involves a series of steps during which specific activities take place or decisions are made. The first step occurs when the Superfund program is notified of a potential site through various mechanisms, including receipt of citizens’ petitions, and referrals or notifications from states, tribes, and other federal agencies. Following notification, a site undergoes a minimal screening process, called a pre- CERCLIS screening, to determine whether a site assessment process is appropriate. Sites deemed appropriate are added to the CERCLIS active site inventory. During the site assessment process, EPA and states collect data to identify, evaluate, and rank hazardous waste sites based on Hazard Ranking System criteria. Using these criteria, EPA and/or its state and tribal partners conduct a preliminary assessment and, if warranted, a site inspection or other more in-depth assessment to determine whether the site warrants short- or long-term cleanup attention. Sites that EPA determines are among the nation’s most seriously contaminated hazardous waste sites are placed on the National Priorities List (NPL) for attention under the federal Superfund program. Cleanup work under CERCLA generally involves two categories of actions: short- term removal actions that address immediate threats to human health and the environment, and long-term remedial actions that aim to permanently or significantly reduce contamination. Only sites on the NPL are eligible for Trust Fund-financed remedial actions, but sites not listed on the NPL may be remediated with private funds, in some instances with EPA oversight. EPA conducts removal actions at both NPL and non-NPL sites. EPA or a PRP will begin the remedial process by conducting a two-part study of the site: (1) a remedial investigation to characterize site conditions and assess the risks to human health and the environment, among other actions and (2) a feasibility study to evaluate various options to address the problems identified through the remedial investigation. The culmination of these studies is a record of decision, which identifies the selected remedy for addressing the site’s contamination and a cost estimate for implementing the remedy. EPA or the PRP may develop preliminary estimates of construction costs and, as the site moves from the study phase into the remedial action phase, a more accurate cost estimate may be developed. The method of implementation for the selected remedy is then developed during remedial design and implemented during the remedial action phase, when actual cleanup of the site occurs. When all construction of the cleanup remedy at a site is finished, all immediate threats have been addressed, and all long-term threats are under control, EPA generally considers the site to be “construction complete.” Sites where additional work is required after construction is completed then enter into the postconstruction phase, which includes actions such as operation and maintenance and conducting 5-year reviews. When EPA in consultation with the state determines that no further site response is appropriate, then EPA may delete the site from the NPL. Figure 2 illustrates the typical Superfund process for cleaning up a site. Thus, EPA may incur a variety of costs in implementing the Superfund program at particular sites. EPA may spend funds to investigate and clean up sites, including short-term removals at any site, and long-term remedial actions at NPL sites. EPA may also incur costs for oversight associated with a site cleanup where a private party is conducting and funding the cleanup. EPA may enter into agreements with PRPs for those parties to conduct cleanups, compel site cleanups by PRPs, or conduct cleanups itself and seek reimbursement for its costs from those parties. EPA’s enforcement of environmental cleanup at Superfund sites begins with the identification of the PRPs, usually early in the cleanup process; continues throughout site cleanup; and often does not conclude until after the site is declared construction complete. EPA identifies PRPs by, among other actions, reviewing documentation related to the site; conducting interviews with government officials or other knowledgeable parties; performing historical research on the site; sampling soil or groundwater at the site; and requesting additional information from relevant parties. In addition to identifying PRPs, EPA attempts to obtain information on the type and amount of hazardous substances shipped to a site by each party and any financial constraints faced by the identified parties. EPA may begin a cleanup process before it has identified PRPs. However, once it identifies PRPs, it typically seeks to reach a settlement with them on their cleanup responsibilities and/or their payment for cleanup costs that EPA incurs. These negotiations generally may take place at any time throughout the site cleanup process. We have previously found that in reaching these settlements, EPA’s and the PRPs’ decisions are influenced by site-specific characteristics and other key considerations, such as the expected cost of site cleanup, the strength of EPA’s evidence of PRP liability, and the number and type of other PRPs. CERCLA established the Trust Fund to support Superfund program activities. EPA generally can use appropriated monies from the Trust Fund for short-term cleanups and for long-term cleanups of NPL sites. For example, EPA may elect to use such funds at sites for which the parties responsible for site contamination cannot be found or are unwilling or unable to clean up a site, to initiate work pending settlement, or in an emergency. Historically, the Trust Fund received revenue from four major sources: taxes on crude oil and certain chemicals, as well as an environmental tax assessed on corporations based on their taxable transfers via appropriations from the general fund of the income;Treasury; fines, penalties, and recoveries from PRPs; and interest earned on the balance of the Trust Fund. In 1995, the authority for the taxes expired and, as of November 2011, had not been reinstated. As of 2011, the Trust Fund’s primary source of revenue is the transfer from the general fund of the Treasury. At the end of fiscal year 2010, the Trust Fund had total assets and liabilities of $3.74 billion, with nearly 55 percent of that total in special accounts. Section 122(b)(3) of CERCLA allows EPA to retain and use funds received pursuant to an agreement with a PRP for purposes of carrying out an agreement. EPA retains those funds in subaccounts of the Trust Fund called “special accounts.” As part of the settlement, those funds placed in a special account may be used for that specific site or may be transferred by EPA to the general portion of the Trust Fund. EPA’s goal in establishing special accounts is to preserve the use of annual congressionally appropriated funds for cleanup at sites without a viable PRP. EPA regions are encouraged to create and use special accounts as an incentive to secure PRP cleanups and to fund EPA’s cleanup when it has lead responsibility. EPA officials said that they believe that PRPs are more willing to settle when assured that their settlement money will generally be used at the site where they hold liability, rather than at another site. According to EPA guidance, regions should strive to use model (standardized) settlement language to establish special accounts. The model language is intended to allow EPA flexibility in deciding for what specific response actions special account funds can be used and therefore when to use these funds. It allows EPA to use the funds for a response action at the site associated with the account, and EPA guidance states that special account funds are site-specific and are generally not available for EPA to use at other sites. The model language also retains EPA’s authority to transfer funds from a special account to the general portion of the Trust Fund for future appropriation by Congress. EPA guidance notes that the language of the actual agreement governs EPA use of a particular special account’s funds. Generally, funds may be deposited in a special account regardless of whether the settling party is performing the work. According to EPA, the agency typically receives funds as a result of agreements entered when the PRPs are unable or unwilling to perform the response action, as is the case in a bankruptcy or an “ability to pay” settlement for parties facing financial difficulties. EPA may also determine that the hazardous substance contributed by a particular PRP was minimal in amount and toxicity compared with other substances at a site and therefore allow that party a de minimis settlement. In addition, PRPs who are conducting some response actions may make payments to EPA to address past or future response actions. EPA’s costs of overseeing the PRPs’ implementation of the work are usually included in future response costs. These payments may be made for the estimated amount of oversight or on a periodic basis.