Out of Sight, Not Out of Mind

To the casual observer, service stations are helpful places where we go to fuel our cars with gasoline and often ourselves with a tempting variety of junk food. Yet, beneath the buzz of activity going on at some gas stations, poorly managed underground storage tanks (USTs) filled with gasoline and diesel are ticking time bombs poised to contaminate groundwater if they begin leaking.

Since the federal UST program was established in 1985, nearly 420,000 leaks (mainly gasoline) have been reported, and two years ago state officials identified leaking USTs as the main source of groundwater contamination in the United States. According to the U.S. Environmental Protection Agency (EPA), approximately 18 percent percent of the estimated 700,000 active USTs are still not in compliance with equipment upgrade rules under the Resource Conservation Recovery Act. While federal regulators say they are generally pleased with the successes they have documented concerning the cleanups of active and abandoned USTs, many point to the challenges that still remain.

A Historical Perspective

In order to better understand the current problems with USTs, it helps to know why service station owners opted to store gasoline and diesel in underground tank systems. The emphasis on using USTs for storing fuel at service stations was spurred by tragedy, according to Wayne Geyer, Executive President of the Steel Tank Institute. Several major fires and explosions from aboveground storage tanks (ASTs) in the United States during the 1960s and 1970s killed a number of firefighters and innocent people. A typical event entailed the overfilling of an unattended AST, which would lead to the spill of combustible liquid around the vessel. When the fluid was accidentally ignited, there would be a major pool fire around the AST. Without adequate venting, the AST would over-pressurize and the tank heads would rupture outwards causing a dangerous explosion.

Increasingly tanks used to store gasoline were buried underground because it removed the potential for a catastrophic tank failure. By 1980, nearly all storage systems -- both private and public retail -- were underground. Soon, however, the shortcomings of USTs started to become apparent when tank owners had to pay for expensive cleanups of groundwater impacted by accidental releases of gasoline from poorly managed USTs.

The proposed law would provide $200 million for cleanup of sites contaminated with methyl tertiary butyl ether (MTBE), a gasoline additive found in 80 percent of reformulated gasoline.

In 1984, because of concerns about risks from leaking tanks, the U.S. Congress established the UST program to monitor the more than two million tanks active at the time, most of which were located at gas stations across the country. Administered by EPA, the UST program was designed to prevent releases of petroleum and hazardous substances into the environment, detect releases when they occurred and clean up any contamination from a release. To prevent further leaks from active tanks and additional cleanups, EPA issued regulations requiring tank owners to either install new leak detection equipment by the end of 1993 and new spill-, overfill- and corrosion-prevention equipment by the end of 1998, or permanently close down or remove their tanks in accordance with federal procedures. As a result, by September 200, approximately 1.5 million tanks had been permanently closed, leaving an estimated 693,107 tanks subject to federal UST program requirements.

To monitor this large number of tanks, EPA has enlisted states' assistance in implementing and enforcing the UST program. As of May 2001, EPA had approved 27 states and the District of Columbia to implement the program with agency oversight and monitoring. Twenty-one additional states operate and enforce their own tank programs under state laws with EPA maintaining limited oversight. These states have implemented requirements similar to the federal requirements.

GAO Report

In 2000, the U.S. Senate's Committee on Environment and Public Works, lead by U.S. Senator Lincoln Chafe (R-RI) and Senator Bob Smith (R-NH), requested that the U.S. General Accounting Office (GAO) conduct a survey to determine the shortcomings of the UST program. GAO complied with the request and then presented its report to the U.S. Senate committee chairmen on May 4, 2001.

The GAO report contained some troubling conclusions. GAO officials determined that the states and EPA cannot ensure that all active USTs have the required leak-, spill-, and overfill-protection equipment installed, nor can they guarantee that the installed equipment is being properly maintained. While the states and EPA regions focus most of their limited resources on the monitoring of active tanks, empty or inactive tanks also require attention to ensure that no soil and groundwater contamination has occurred. Half of the states have not physically inspected all of their tanks and several others have not conducted frequent enough inspections to ensure that the tanks' compliance with program requirements. Moreover, most states and EPA lack authority to use the most effective enforcement tools and many state officials acknowledged that additional enforcement tools and resources were needed to ensure tank compliance.

The report further concluded that EPA has the opportunity to correct these limitations within its own regions and to help states correct them through its new tank program initiatives. However, the agency has yet to define many of the implementation details, so it is difficult to determine whether the proposed actions will be sufficient to ensure more inspection coverage and more effective enforcement, especially within the states.

GAO made four recommendations to the EPA Administrator Christie Whitman.

  • EPA should address the remaining non-upgraded tanks by working with the states to review the USTs that pose the greatest risk; set up timetables for the owners, states or EPA to remove or close these tanks; and take enforcement actions against owners and operators who continue to operate USTs without the required equipment.
  • EPA should supplement the agency's more general training support, such as providing manuals and materials, by having each EPA region work with each of the states in its jurisdiction and determine specific training needs.
  • EPA should negotiate with each state to reach a minimum frequency for physical inspections of all its tanks.
  • EPA should present to the Congress an estimate of the total additional resources the agency and the states need to conduct the training, inspection and enforcement actions necessary to ensure tank compliance with federal regulations.

Increasingly tanks used to store gasoline were buried underground because it removed the potential for a catastrophic tank failure.

Proposed UST Legislation

On December 19, 2001, in the wake of the GAO report, Sen. Chafe introduced legislation -- the Underground Storage Tank Compliance Act of 2001 (S. 1850) -- to help prevent groundwater contamination caused by leaking USTs. Supporters of S. 1850 want to expand the uses of money from the existing Leaking Underground Storage Tank (LUST) Trust Fund. The trust fund was established in 1986 to provide money to clean up leaks in emergency cases where tank owners were unwilling or financially unable to do so. The proposed legislation would allow the trust fund to be used to require the inspection of all tanks every two years, while increasing federal emphasis on training of UST operators. The legislation also would provide $200 million for cleanup of sites contaminated with methyl tertiary butyl ether (MTBE). MTBE is a gasoline additive found in 80 percent of reformulated gasoline that is the source of contamination of many drinking water supplies at LUST sites.

Additionally, S. 1850 would allow states to prohibit gasoline deliveries at facilities that are not in compliance with federal and state regulations. As well, the bill would apply regulations to tanks located at federal facilities and on tribal lands. Finally, the legislation would provide $460 million to improve compliance with UST regulations, which the GAO identified as a critical piece of the solution.

Even though most lawmakers agree with the basic objectives of S. 1850, there are still many details that have to be worked out in order to ensure the passage of the bill. For example, the Bush administration supports the fundamental goals of the legislation, yet it has some concerns that the bill will require EPA to issue rules on tight timeframes regarding the more flexible uses of funds that would be allowed under the bill.

Likewise, state officials have expressed concerns that the collective requirements of S. 1850 will involve substantial increases in state workloads. Testifying at a U.S. Senate hearing on May 8, 2002, concerning the passage of the proposed tank legislation, Kathleen Stiller, chair of the Association of State and Territorial Solid Waste Management Officials' Tanks Subcommittee, said that state officials want assurances the increased funding in the bill for additional enforcement, remediation and training requirements will be available to them in future years. According to Stiller, some state officials are also concerned about the bill's required inspections every two years, which she said might not be possible for some states. At press time in May, the bill is still under review and has not yet been put up for a vote by the full membership of the U.S. Senate.

Hopefully, our lawmakers will be able to reach a compromise that will allow this bill to move forward and become law this year. If implemented, this new statute should help ensure that fuels stay where they belong and thereby prevent underground releases that pose dangerous risks to our already limited drinking water supplies.

Leakbusters: Proven Technology Fights UST Releases

The American Petroleum Institute estimates that there are currently 180,000 retail service stations in the United States that hold more than two billion gallons of gasoline and diesel fuel in USTs at any given time. A UST is defined as a tank and any underground piping connected to the tank that has at least 10 percent of its combined volume underground. A typical gasoline station has a storage capacity of 30,000 or 40,000 gallons, which may be refilled on a weekly basis. In the past, these storage tanks were subjected to spills from overfilling the tanks, and other leaks were caused by corrosion of the tanks. In the wake of the more stringent laws that went into effect in December 1998, station owners have taken several important steps to reduce these risks:

  • Underground moisture can corrode steel tanks. New fiberglass tanks and steel tanks lined with fiberglass and other durable coatings can prevent corrosion.
  • Steel tanks can also be protected from corrosion with cathodic protection systems. Corrosion is essentially caused by steel slowly dissolving into the surrounding moisture. Applying a small electrical charge to the tank helps prevent the steel from dissolving.
  • A variety of overfill protection devices prevent operators from overfilling storage tanks: alarms let the operator know when the tank is getting full; automatic shut-off switches stop the pumping of the motor fuel into the tank before the tank completely fills; ball float valves close the vent pipe when the tank is getting full. This creates a backpressure that tells the person filling the tank that the tank is almost full.
  • All tanks are equipped with catchment basins - large "buckets" located around the fill pipe that catch any fuel that may spill when the delivery hose is uncoupled from the fill pipe.
  • Leak detection devices send an alarm signal if the tank is leaking fuel. These systems can detect leaks as small as 0.1 gallon per minute.
  • Monitors can also detect the presence of gasoline vapors in the soils around the UST or can detect small amounts of fuel floating on the groundwater under the UST.


The Underground Storage Tank Compliance Act of 2001 (S. 1850) -- thomas.loc.gov/

U.S. General Accounting Office's Report "Improved Inspections and Enforcement Would Better Ensure the Safety of Underground Storage Tanks" (Report #GAO-01-464) -- www.gao.gov

American Petroleum Institute -- www.api.org

The Steel Tank Institute -- www.sti.org

This article originally appeared in the July/August 2002 issue of Environmental Protection, Vol. 13, No. 7, p. 42.

This article originally appeared in the 07/01/2002 issue of Environmental Protection.

Featured Webinar