In the 1980s, EPA determined that many of the roughly 2.2 million underground storage tanks (USTs) in the United States, most of them storing petroleum products, were leaking. Many other tanks were nearing the end of their useful life expectancy and were expected to leak in the near future. Approximately 50% of the U.S. population relies on ground water for their drinking water, and states were reporting that leaking underground tanks were the leading source of groundwater contamination. In 1984, Congress responded to this public health and environmental threat and established a leak prevention, detection, and cleanup program for USTs containing chemicals or petroleum by establishing an underground storage tank regulatory program in Subtitle I of the Solid Waste Disposal Act, also known as the Resource Conservation and Recovery Act (RCRA). Subtitle I directed EPA to establish operating requirements and technical standards for tank design and installation, leak detection, spill and overfill control, corrective action, and tank closure. The universe of regulated tanks was extremely large and diverse, and included many small businesses. Consequently, EPA phased in the tank regulations over a 10-year period (1988 through 1998). Strict standards for new tanks took effect in 1988, and all tanks were required to comply with leak detection regulations by late 1993. All tanks installed before 1988 had to be upgraded (with spill, overfill, and corrosion protection), replaced, or closed by December 22, 1998. In 1986, Congress established a response program for leaking petroleum USTs through the Superfund Amendments and Reauthorization Act (SARA; P.L. 99-499 ), which amended RCRA Subtitle I. The amendments authorized EPA and states to respond to petroleum spills and leaks. SARA also amended the Internal Revenue Code of 1986 to create the Leaking Underground Storage Tank (LUST) Trust Fund to help EPA and states cover the costs of responding to leaking USTs in cases where UST owners or operators do not clean up a site. EPA and the states have used the annual LUST Trust Fund appropriation mainly to oversee and enforce corrective actions performed by responsible parties. The law also authorized the use of funds to conduct corrective actions where no responsible party has been identified, where a responsible party fails to comply with a cleanup order, in the event of an emergency, and to take cost recovery actions against parties. EPA and states have been successful in getting responsible parties to perform most cleanups. In these cases, the cleanup costs typically have been paid for by a state fund (discussed below), the responsible party, and/or private insurance. The 1986 law further directed EPA to establish financial responsibility requirements to ensure that UST owners and operators are able to cover the costs of taking corrective action and compensating third parties for injuries and property damage caused by leaking tanks. As mandated, EPA issued regulations requiring most tank owners and operators selling petroleum products to demonstrate a minimum financial responsibility of $1 million. Alternatively, owners and operators could rely on state assurance funds to demonstrate financial responsibility, saving them the cost of purchasing private insurance. Most states established financial assurance funds. Unlike the federal LUST Trust Fund, state funds often are used to reimburse financially solvent tank owners and operators for some or all of the costs of remediating leaking tank sites. Revenues for state funds typically have been generated through tank fees and petroleum fees; collectively, these funds have provided more cleanup funds than the federal LUST Trust Fund. A 2009 survey of state financial assurance funds, conducted by the Vermont Department of Environmental Conservation, showed that, cumulatively, states had provided more than $17 billion through their funds to support the cleanup of leaking tank sites. During 2009, state funds collected $1.38 billion in annual revenues and paid out a total of $875 million, while outstanding claims against state funds reached $2.69 billion, up from $1.32 billion in 2006. States reported that the average cost of cleaning up a leaking tank site was roughly $127,000. The number of sites with claims also has increased annually, growing from 159,909 in 2006 to 173,717 in 2009. While 10 states have made a transition to private insurance, 20 states have extended their funds' original sunset date to address the backlog of leaking tanks. The LUST Trust Fund is funded primarily through a 0.1 cent-per-gallon motor fuels tax which began in 1987. The Energy Policy Act of 2005 ( P.L. 109-58 ) extended the tax through September 2011. During FY2009, the fund earned approximately $107 million in interest and $169 million in tax receipts (down from $228.3 million in FY2007). The estimated total revenue value of the trust fund was roughly $276 million for the fiscal year. At the start of FY2010, the fund had an unobligated balance of approximately $3.0 billion. For a number of years, Congress appropriated approximately $72 million annually from the LUST Trust Fund to support the LUST response program. The Energy Policy Act of 2005 (EPAct; P.L. 109-58 ) authorized new uses of the trust fund and added new appropriations authorities to fund Subtitle I leak prevention and detection activities, in addition to cleanup activities. In the Consolidated Appropriations Act, 2008 ( P.L. 110-161 ), Congress provided $105.8 million from the fund, including roughly $72 million for the cleanup program and $33.8 million for the UST leak prevention program, reflecting the broadened range of authorized uses of the fund under EPAct. EPA typically has allocated approximately 81% of the annual trust fund appropriation to the states in the form of cooperative agreements, and 4% to support LUST-eligible activities on Indian lands. The agency has used the remaining 15% for its program responsibilities. EPAct ( P.L. 109-58 , § 1522) specified that EPA must allot at least 80% of the LUST Trust Fund appropriation to the states. Under cooperative agreements with EPA, the states receive grants to help cover the cost of administering the LUST program. States have used most of their LUST program grants to hire staff for technical oversight of corrective actions performed by responsible parties. Typically, they have used about one-third of their LUST grants for cleaning up abandoned tank sites and undertaking emergency responses. In FY2009, EPA provided approximately $63 million through state cooperative agreements and to tribes for the cleanup program and used roughly $11 million to meet its responsibilities. EPA provided another $34.4 million from the trust fund for state and tribal grants to implement and enforce the UST leak prevention program. EPA uses its portion of the appropriation to oversee cooperative agreements with states, implement the LUST corrective action program on Indian lands, and support state and regional offices. EPA priorities in the LUST program have included reducing the backlog of confirmed releases; promoting better and less expensive cleanups; providing assistance to Indian tribes; assisting with the cleanup of more complicated sites, especially sites contaminated with MTBE; and implementing the Energy Policy Act provisions. More recent work areas for EPA's UST program involve evaluating the compatibility of fuel storage tanks with alternative fuels, and evaluating the transport and degradation characteristics of ethanol and biodiesel blends. EPA reports that since the federal underground storage tank program began, more than 1.7 million substandard underground storage tanks subject to regulation have been closed and, overall, the frequency and severity of leaks from UST systems have been reduced significantly. Through September 2009, 611,449 tanks remained in service (at approximately 223,000 sites) and subject to UST regulations. A total of 488,496 releases had been confirmed, and 463,060 cleanups had been initiated. Approximately 79.5% (388,331) of all reported releases had been cleaned up, and the backlog of sites requiring remedial action dropped to 100,165 sites. During FY2009, 7,168 releases were confirmed, and 12,944 cleanups were completed. Despite these cleanup achievements, program needs remain significant. Although EPA expects that private parties will pay for most cleanups, states estimated in 2007 that $12 billion was needed to remediate at least 54,000 tank sites that lack viable owners. Moreover, many tank owners and operators have yet to achieve full compliance with EPA technical regulations that are intended to prevent and detect leaks. EPA had estimated that by FY2001, 89% of USTs had upgraded tank equipment to meet federal requirements. However, the Government Accountability Office (GAO) reported that because of poor training of tank owners, operators, and other personnel, about 200,000 (29%) USTs were not being operated or maintained properly, thus increasing the risk of leaks and ground water contamination. GAO also reported that only 19 states physically inspected all their tanks every three years (the minimum EPA considered necessary for effective tank monitoring) and, consequently, EPA and states lacked the information needed to evaluate the effectiveness of the tank program and take appropriate enforcement actions. Among its initiatives to improve compliance, EPA revised the definition of compliance ("significant operational compliance") to place greater emphasis on the proper operation and maintenance of tank equipment and systems. At the close of FY20009, EPA reported that, nationwide, 79.3% of recently inspected UST facilities were in compliance with the release prevention regulations, 76.3% were in compliance with the leak detection regulations, and 66.4% of facilities had complied with the combined requirements. To address some of the program weaknesses and to improve leak prevention, Congress added new requirements to the UST regulatory program for EPA, states, and UST owners and operators, under the Energy Policy Act of 2005. The new provisions included requirements for inspections and for operator training. (See discussion below.) As the UST program matured during the 1990s, and states and EPA were making solid progress in addressing tank leaks, a new problem emerged.