What are Underground Storage Tanks?

What Is a UST?

A UST is an underground storage tank and the related piping, ancillary equipment, and containing systems. Some USTs are federally regulated for environmental, public health, and occupational safety reasons.

An aboveground storage tank is called an AST, but they are regulated separately.

What Are Underground Storage Tanks?

Underground storage tanks don't need to be entirely – or even mostly – underground.

Under federal law, an underground storage tank's definition is any tank (with associated piping) that has more than 10% of its combined volume underground.

What Is an Underground Storage Tank Used For?

There are many different uses for underground tanks. Residential properties can have an underground tank to serve as a septic system or store heating oil. There are also many commercial uses, including the most common: underground fuel storage tanks.

Are Underground Storage Tanks Hazardous?

They can be. The reason we need underground storage tank regulations is that underground tanks frequently contain hazardous liquids and gases.

The greatest potential hazard of an UST is that a leak can seep into the soil and contaminate groundwater, which nearly half of all Americans rely on as a source of drinking water.

Before underground storage tank regulations were instituted by the U.S. Environmental Protection Agency (EPA) in the 1980s, most underground fuel tanks and other USTs were made of bare steel, which corroded over time resulting in leaks. Faulty installation, inadequate operating procedures, and poor maintenance have also caused the uncontrolled release of UST contents.

Aside from groundwater and other environmental contamination, underground fuel tanks can present other risks, including the potential for fire and explosion. Working around and in an underground tank can present special hazards to the worker(s), which is why the Occupational Safety and Health Agency (OSHA) also has relevant standards.

What Federal EPA Regulations Do USTs Have?

First, not all underground storage tanks are regulated.

For the ones that do, federal regulations are divided into three categories:

• Technical requirements to detect leaks and spills, reduce the chances they occur, and secure prompt cleanup.
• Financial responsibility requirements to ensure that owner/operators have the resources to pay for cleanup costs and compensate third parties.
• The objectives that a state UST regulatory program must meet so that they're allowed to operate in lieu of the federal program.

Which Underground Storage Tanks are Federally Regulated?

The EPA only regulates underground storage tanks containing petroleum or certain other hazardous substances. The list of hazardous substances is long and can be found in the federal code.

The vast majority of regulated USTs store petroleum products. As of September 2021, the EPA says there are roughly 540,000 active petroleum USTs and 2700 USTs containing "other hazardous substances."

In other words, the EPA's UST regulations largely apply to underground fuel tanks like the underground gasoline storage tanks that supply gas pumps. That includes filling stations meant for the public as well as private filling stations used by fleet service operators and local governments.

Federal regulations do NOT apply to:

• Farm and residential tanks that hold motor fuel used for noncommercial purposes with a capacity of 1,100 gallons or less
• Tanks storing heating oil to be used on the premises
• Tanks on or above the floor of underground areas like basements or tunnels
• Septic tanks and systems for collecting stormwater and wastewater
• Flow-through process tanks
• Pipeline facilities as well as liquid traps directly related to oil/gas production/gathering operations
• Surface impoundments, pits, ponds, or lagoons
• Equipment/machinery that contains regulated substances for operational purposes
• Tanks with a capacity of 110 gallons or less
• Tanks that contain a regulated substance beneath the minimum concentration
• Emergency spill and overfill tanks

Keep in mind that state and local governments may have their own regulations that apply to federally exempt underground tanks.

Who Implements and Enforces Underground Storage Tank Regulations?

In the 1980s, the U.S. Congress passed a series of laws, found in 40 CFR 280, to address the problem of leaking underground storage tanks. At the time, USTs were made of bare steel that tended to corrode over time, leading to environmental contamination.

The original regulations required UST owners/operators to add spill, overfill, and release detection equipment to their tanks. However, there were no requirements for the equipment to be inspected. In 2015, the regulations were revised with requirements for operation, maintenance, and training. UST operators were given until late 2018 to meet the new requirements.

While the EPA issues federal regulations related to USTs, they're implemented mostly by states. In states without an approval program, both sets of regulations apply and the EPA works with state officials to coordinate enforcement.

If a state has an approved UST program, owner/operators only have to deal with the state-level regulations. The District of Columbia, Puerto Rico, and 38 states have approved state UST programs for this purpose. State programs have to enforce rules that are equivalent to federal regulations, but they can also add more stringent requirements.

Federal Requirements for Underground Storage Tank Systems

Federal underground storage tank regulations set standards for several things: the equipment itself, its operation and maintenance, record-keeping and reporting requirements, and an obligation to take financial responsibility for UST-related problems. We'll go into detail on each of these areas below, but remember, these are federal requirements. Your state or territorial regulations may be different.

Technical Requirements for Underground Storage Tank Systems

The technical requirements for federally regulated UST systems are extensive. Tanks must meet certain requirements for spill and overfill prevention, corrosion protection, release detection, secondary containment, and material compatibility. Many of the exact specifications vary based on the size of the tank or deliveries, the age of the UST system or its components, and the type of substance, as well as other factors.

UST Inspection, Operation, and Maintenance

Federal regulations require UST operators to conduct regular inspections of underground storage tank systems – either themselves or by hiring a third party. The EPA sets a schedule for the inspection of different components. For example, you should inspect:

• spill prevention and release detection equipment every 30 days
• containment sumps and hand-held release detection equipment once a year
• spill buckets and overfill prevention equipment every three years

There are also specific guidelines dictating operation, maintenance, and repair for UST systems, like:

• what to do before, during, and after a UST is filled
• what monitoring measures you have to take and how often
• how to investigate and respond to a UST release
• when you can repair equipment and when you have to replace it
• what inspection and testing measures have to be performed after repair or replacement
• your responsibilities before, during, and after a UST closure

To ensure that all of these guidelines are followed correctly, facilities must have trained and designated UST operators. UST operators are classified according to their level of responsibility:

• Class A operators have primary responsibility for operating and maintaining the UST system according to UST regulations. They need to have a general knowledge of the regulations that apply to them.
• Class B operators have day-to-day responsibility for implementing UST regulations. They need to understand the operation and maintenance requirements for UST systems.
• Class C operators are responsible for the immediate response to a problem at a UST facility. These are employees like gas station attendants, who need to know how to respond to an alarm or emergency.

One person can fill multiple roles, as long as they have the training to fulfill their responsibilities.

Financial Responsibility for USTs

UST operators have to demonstrate the financial ability to clean up their site, correct environmental damage, and compensate third parties if a release does occur. There are a few ways to do this:

• Get insurance coverage
• Demonstrate self-insurance through corporate guarantees, surety bonds, or letters of credit
• Put the required amount of money into an independently administered trust fund
• Rely on coverage provided by a state financial assurance fund

The amount of financial coverage depends on the type and size of your business.

Reporting and Record-Keeping Related to Underground Storage Tanks

Federal regulations require you to report certain changes in Underground Storage Tank use to your implementing agency, like bringing a UST system into use, acquiring one, switching a UST to certain substances, or permanent closure. You also have to report suspected releases from your UST. Once you confirm a release, you must report your actions or your plan to correct the damage the release caused. Federal record-keeping requirements are more extensive. You're required to keep records of most mandatory actions for a certain period of time.

What is UST Training and Where Do You Get It?

UST training teaches operators how underground storage tanks work and how to respond to UST-related emergencies effectively and according to law.

Owners and workers at UST facilities need UST training that matches their state and operator class:

• Class A operators hold primary responsibility for on-site operation and maintenance of an UST system according to regulations. They're required to have general knowledge.
• Class B operators have the day-to-day responsibility for implementing UST regulations. They need a more in-depth understanding
• Class C operators are responsible for responding to UST-related emergencies. They need to know how to resolve and respond to spills, leaks, and fires.

We offer online UST training for all states and classes. It's inexpensive, self-paced, and convenient. Enroll today!