Learn About Underground Storage Tanks

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What is an UST?

An underground storage tank system is a tank and any underground piping connected to the tank that has at least 10 percent of its combined volume underground. The federal UST regulations apply only to UST systems storing either petroleum or certain hazardous substances.

When the UST program began, there were approximately 2.1 million regulated UST systems in the United States. Today there are far fewer since many substandard UST systems have been closed. For the most current statistics, see UST Performance Measures. Nearly all USTs regulated by the underground storage tank requirements contain petroleum. UST owners include marketers who sell gasoline to the public (such as service stations and convenience stores) and non marketers who use tanks solely for their own needs (such as fleet service operators and local governments). EPA estimates that fewer than 2,000 tanks hold hazardous substances covered by the UST regulations.

Why be concerned about USTs?

Until the mid-1980s, most USTs were made of bare steel, which is likely to corrode over time and allow UST contents to leak into the environment. Faulty installation or inadequate operating and maintenance procedures also can cause USTs to release their contents into the environment.

The greatest potential hazard from a leaking UST is that the petroleum or other hazardous substance can seep into the soil and contaminate groundwater, the source of drinking water for nearly half of all people living in the United States. A leaking UST can present other health and environmental risks, including the potential for fire and explosion. The reports below discuss USTs and ground water.

EPA's 2008 Report on the Environment
2008 report about trends in human health and the environment
- Chapter 3: Water (PDF) (66 pp, 5.1MB, About PDF) Section 3.3.1
EPA’s National Water Quality Inventory 2000 Report
2000 report prepared under Section 305(b) of the Clean Water Act. See Chapter 6 for information about groundwater quality and underground storage tanks.
The Ground Water Report to the Nation: A Call to Action (PDF) (164 pp, 15.7 MB, About PDF)
2007 report from the Ground Water Protection Council. Section 7 addresses ground water and underground storage tanks

How have Congress and EPA responded to concerns about USTs?

To address a nationwide problem of leaking USTs, Congress passed a series of laws to protect human health and the environment.

Year	Congressional Action
1984	Subtitle I was added to the Solid Waste Disposal Act through the Hazardous and Solid Waste Amendments. Created a federal program to regulate USTs containing petroleum and hazardous chemicals to limit corrosion and structural defects and thus minimize future tank leaks. Directed EPA to set operating requirements and technical standards for tank design and installation, leak detection, spill and overfill control, corrective action, and tank closure.
1986	Subtitle I was amended through the Superfund Amendments Reauthorization Act. Authorized EPA to respond to petroleum spills and leaks. Directed EPA to establish financial responsibility requirements for UST owners and operators to cover the cost of taking corrective actions and to compensate third parties for injury and property damage caused by leaking tanks. Created the Leaking Underground Storage Tank Trust Fund, which is used to oversee cleanups by responsible parties, enforce cleanups by recalcitrant parties, and pay for cleanups at sites where the owner or operator is unknown, unwilling, or unable to respond, or where emergency action is required.
2005	Energy Policy Act of 2005 amended Subtitle I of the Solid Waste Disposal Act. Added new leak detection and enforcement provisions to the program. Required that all regulated USTs be inspected every three years. Expanded the use of the LUST Trust Fund. Required EPA to develop grant guidelines regarding operator training, inspections, delivery prohibition, secondary containment, financial responsibility, public record, and state compliance reports on government USTs. Required EPA to develop a strategy and publish a report regarding USTs in Indian Country.
2009	American Recovery And Reinvestment Act of 2009 (Recovery Act). Provided a one-time supplemental appropriation of $200 million from the LUST Trust Fund to EPA for cleaning up leaks from federally regulated USTs. Majority of the money ($190.7 million) allocated to states and territories in the form of assistance agreements to address shovel ready sites within their jurisdictions.
2015	The 2015 UST regulation changed certain portions of the 1988 underground storage tank technical regulation. Added periodic operation and maintenance requirements for UST systems. Added requirements to ensure UST system compatibility before storing certain biofuel blends. Removed past deferrals for emergency generator tanks, airport hydrant systems, and field-constructed tanks. Updated codes of practice.

A complete version of the law that governs underground storage tanks is available in the U.S. Code, Title 42, Chapter 82, Subchapter IX. This law incorporates amendments to Subtitle I of the Solid Waste Disposal Act as well as the UST provisions of the Energy Policy Act of 2005 and gives EPA the authority to regulate USTs.

Additional information on how EPA implemented the American Recovery and Reinvestment Act.

Additional information on EPA's laws and regulations pertaining to USTs.

Who implements the UST program?

EPA recognizes that, because of the large size and great diversity of the regulated community, state and local governments are in the best position to oversee USTs. States may have more stringent regulations than the federal requirements. If you are interested in requirements for USTs, contact your state UST program for information on state requirements.

If you have a question that involves USTs in Indian country, contact your EPA regional office. EPA has responsibility for, and authority over, USTs in Indian country.

Do all tanks have to meet federal EPA regulations?

These USTs do not need to meet federal requirements for USTs:

Farm and residential tanks of 1,100 gallons or less capacity holding motor fuel used for noncommercial purposes;
Tanks storing heating oil used on the premises where it is stored;
Tanks on or above the floor of underground areas, such as basements or tunnels;
Septic tanks and systems for collecting storm water and wastewater;
Flow-through process tanks;
UST systems of 110 gallons or less capacity; and
Emergency spill and overfill tanks.

However, some state and local regulatory authorities may regulate these types of tanks so check where your USTs are located.

What are the federal requirements for USTs?

In 1988, EPA issued UST regulations divided into three sections: technical requirements, financial responsibility requirements, and state program approval objectives (as described below).

Technical requirements for USTs
EPA's technical regulations for USTs are designed to reduce the chance of releases from USTs, detect leaks and spills when they do occur, and secure a prompt cleanup. UST owners and operators are responsible for reporting and cleaning up any releases. See Preventing Releases, Detecting Releases, and Cleaning Up Releases. EPA produced a 36-page booklet Musts For USTs that clearly presents the UST regulatory requirements.

Financial responsibility regulations for USTs
EPA designed the financial responsibility regulations to ensure that, in the event of a leak or spill, an owner or operator will have the resources to pay for costs associated with cleaning up releases and compensating third parties. See Financial Responsibility. EPA produced a 16-page booklet called Dollars And Sense that clearly presents these regulatory requirements.

State program approval objectives
Subtitle I allows state UST programs approved by EPA to operate in lieu of the federal program, and EPA's state program approval regulations set standards for state programs to meet. See State Program Approval (SPA) for more information. States may have more stringent regulations than the federal requirements.

Need more information?

EPA's Underground Storage Tank Program Directory provides contact information for EPA headquarters and regional personnel as well as contact information for state and territory programs.

EPA's Underground Storage Tank Indian Country Program Directory provides information about Tribal UST program contacts, Tribal UST contacts with federal credentials, EPA headquarters Tribal UST contacts, EPA regional UST and LUST offices, and UST technical assistance contacts for Tribes.

EPA’s Program Facts provide an overview of the UST program and some basic facts.