Understanding Underground Storage Tanks: Dangers and Regulation

Understanding Underground Storage Tanks: Dangers and Regulation


An underground storage tank (UST), in the Environmental Protection Agency’s (EPA) definition, is any tank with ancillary piping that has at least 10% of its combined volume submerged underneath the ground. Federal EPA regulations only apply to USTs that store either petroleum or certain other hazardous substances, such as methane, solvents, and ethylene glycol.

According to the EPA, the following tanks are also exempt from regulation,

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

State or territory-based regulations also apply to USTs, so there may also be certain state-specific definitions of what constitutes a UST in lieu of the federal guidelines.

Potential Dangers

Some of the dangers posed by USTs include leakage, which might seep into groundwater. Groundwater has been estimated to supply about 50% of the nation with drinking water.

Also, until the mid-1980s, most USTs were comprised entirely of bare steel, which over time corrodes, leading to a higher chance of vulnerability for breaks, punctures, and leakage. Mishandling the installation of underground storage tanks can also be a potential problem, risking environmental damage.

Petroleum-containing USTs have proven the greatest hazard, as they can most harmfully affect groundwater. In some cases, a leaking petroleum UST can lead to fire and explosions.

Removal of leaking underground storage tanks (LUST) petoleum remediation site in Wisconsin

Leaking Underground Storage Tank (LUST) Remediation Site in Wisconsin.

Federal Regulations

In 1984, the Environmental Protection Agency responded to this potential threat to drinking water by adding regulation in the form of Subtitle I onto the Solid Waste Disposal Act (which in turn is part of the Resource Conservation and Recovery Act), which applies directly to USTs and their overseers.

By 1985, uncovered steel tanks without any outer protection were banned. In 1986, these stipulations on underground storage tanks were again amended, and Congress created the Leaking Underground Storage Tank (LUST) trust.

The two purposes of the LUST trust are to

  • oversee cleanups of leakage by the responsible parties, and
  • to pay for emergency cleanups, or where the owner of a ruptured UST is either unknown, unable to respond, or unable to pay for the damages.

And in 1988, an amendment on USTs took effect, which allowed approved state programs to operate outside of federal regulations.

Since the 1980s, Subtitle I has been since amended to help forces more on proper inspections, training, education on containment, spill prevention, and fiscal responsibility. In 2009, Congress allocated $200 million from the LUST trust to the EPA to clean up leaking USTs across the nation.


If you would like more information on underground storage tanks, or if you need assistance with your own leaking UST, please give Environmental Remediation Experts a call at 888-681-8923 or click here to email us.


Photo credit: Wisconsin Department of Natural Resources at compfight