Understanding Underground Storage Tanks

Learn about different compliance in properly disposing of underground storage tanks

What is an Underground Storage Tank (UST)?

Underground Storage Tanks, or USTs, are used to store petroleum products, chemicals, and other hazardous materials underground. USTs are typically made of steel or fiberglass and can range in size from a few hundred to several million gallons.

The key advantage of a UST is that it helps to protect these materials from weathering, evaporation, and leaking into the groundwater. However, USTs can also be difficult and expensive to clean up if they leak. As a result, it’s essential to have a professional inspect and maintain your UST regularly.

Why are UST Systems Regulated?

UST systems are heavily regulated because they severely threaten the environment. USTs are typically used to store petroleum products; if these products leak into the ground, they can contaminate soil and water resources. In addition, leaking USTs can release harmful vapors into the air, posing a health risk to nearby residents. As a result of these risks, state and federal governments have enacted strict regulations governing the construction, operation, and maintenance of UST systems.

These regulations help minimize the chance of a leak and ensure that any leaks are quickly detected and repaired. By protecting our environmental resources, these regulations help to keep our communities safe and healthy.

Who Regulates UST Systems?

Congress instructed the US Environmental Protection Agency (EPA) to develop underground storage tank regulations in 1984. The federal government issued this effective in December 1988 that delegated UST regulatory authority to pre-approved state programs instead. States are primarily responsible for carrying out the UST program, and their requirements might be more severe than what is federally regulated.

Do All Tanks Have to Meet Federal EPA Regulations?

The following tanks are not subject to the federal EPA regulations:

  • Tanks holding motor fuel that are 1,100 gallons or less and used for noncommercial purposes on farms or in residential areas
  • Storage tanks for heating oil used on the property where the tank is located
  • Tanks that are on the floor or above it in underground areas, such as basements or tunnels
  • Septic tanks for collecting stormwater and wastewater
  • Flow-through process tanks
  • Tanks that hold 110 gallons or less
  • Emergency spill and overfill tanks

Some state and local authorities may have rules about these kinds of tanks. Find out if your tanks are subject to any regulations from your state or local government’s website.

What are the Responsibilities of UST Owners or Operators?

As of 2015, the EPA has revised UST regulations. The requirements for owners and operators are as follows.

Federally regulated USTs must:

  • Register with the appropriate regulatory authority
  • Meet leak detection requirements
  • Meet spill, overfill, and corrosion protection requirements

Additionally, owners and operators must:

  • Meet financial responsibility requirements
  • Check the site for leaks, spills, and overfills
  • Ensure you follow all the rules when you install a new tank or close an old one
  • Keep and maintain records of everything as required
  • Conduct periodic corrosion protection and leak detection systems

Reasons for Removal of Underground Storage Tanks

The reason for removing USTs can vary. Some of the most common causes include:

Out-of-Use Tanks

Sometimes, a property owner does not use their UST anymore. Perhaps their business no longer requires this type of underground storage tank. Or, maybe a newer UST is in use, and the old one remains underground. Unusable tanks threaten the environment, and best practices and laws suggest removal.

Leaking Tanks

The owner or operator of a UST must act if it leaks. A leaking UST might present a problem of soil and water resource contamination. Additionally, vapors might escape the tank and enter buildings, posing a health risk to occupants. UST removal is often the best way to mitigate these risks.

Replacing a Tank

Some older and less updated USTs may necessitate removal and replacement to bring them into compliance with new regulations. For example, more recent upgrades include double- or triple-walled tanks, which now meet most jurisdictions’ regulatory requirements.

The Underground Storage Tank Abandonment Process

Obtaining underground storage tank abandonment permits requires meeting many requirements. These include:

UST Removal Permitting

Generally, the City, County, and State Environmental Agencies regulate underground storage tank abandonment. The UST owner or operator must contact the agency to determine the requirements and permitting process.

Abandonment in Place

In special cases where it is necessary to stabilize an underground tank, filling it with a cement slurry may be the only option. The method is only allowable when it’s impossible to remove the tank without compromising structural integrity, such as when it lies directly below a building perimeter or retaining wall. In addition to the original UST abandonment permit, an additional special license is necessary if such a case occurs.

Fieldwork for the Underground Storage Tank Abandonment and Removal Process

To obtain a “No Further Action Certificate,” it is mandatory that you adhere strictly to the standard procedures and protocols set forth by the environmental agency. Various qualifications and fees are required to file a successful application for a UST abandonment permit; some of these include:

  • Additional licenses from local regulatory authorities
  • An excavation executed correctly
  • Testing for soil contamination performed
  • Efficient remediation methods implemented

An oversight agency must also approve the process. The lead environmental agency must approve a final report with geological and toxicological certification and a waste disposal record.

Preparing the Site for UST Removal

Several steps are required to ensure environmental compliance and public safety before starting any excavation, aiming to assess the UST’s chemical substances and avoid potential leaks, spills, contamination, or danger during and after removal. Here are some of the key steps:

Emptying the Tank

The contractor who works with underground storage tanks must empty the tank of any liquids or residue. Emptied tanks must be injected with inert gas because their contents are usually flammable and poisonous. This process must be overseen and certified by a professional toxicologist. Additionally, the transportation and disposal of these materials may require permits and regulation by government agencies.

Underground Storage Tank Inert Process

If the UST was recently emptied of combustible materials, replacing those flammable gasses with non-flammable gas is crucial. USTs are often effectively dispersed with dry ice (carbon dioxide) implants. Underground storage tank contractors must reduce the explosion risk even if the inerting process is successful. Part of UST abandonment involves hot work training, certification, and permits so that contractors can avoid flames or sparks.

Certified Clean Tanks

Only specific certified professionals can declare a UST clean. It means there are no sludge, debris, or vapors inside the tank. With a clean certificate, more options are available on-site for methods that use heat or flames. These methods comprise what is known as “hot work.”

Excavating the Site

Soils Management Plans are generally the primary guidebook for excavation professionals when removing a UST and backfilling and compaction testing. Removing the tank will start with digging using construction equipment such as backhoes or excavators.

Confirmation Soil Sampling

Soil testing is essential to ensure no harmful materials are around the UST. A professional geologist or engineer will help with this. If the soil is clean, the removed soil can be used to fill in the hole. If the soil is contaminated, it must be removed using special procedures for hazardous materials. More testing will be needed to determine what else needs to be done to make the area safe again.

Disposal of the UST Materials

Recycling the ground requires cleaning it after removing the USTs. USTs are usually pressure washed and rinsed on-site before transport. Lastly, EPA requires that all waste, from construction debris to rinse water, be disposed of properly.

Underground Storage Tank Abandonment Report Writing

The professional geologist or engineer in charge of the project will submit a report called the “Underground Storage Tank Abandonment Report.” This report will tell what happened on-site and what the soil analysis found. The report will say what to do next if more action is needed. This document must be signed and stamped by a professional geologist or engineer. The property owner and other agencies will also receive a report copy.

FAQs About UST

You must call your implementing agency and tell them about any suspected leaks. You can then find out if these suspected leaks are actual leaks using the following investigative steps:

  • Test the UST system to see if it is airtight
  • Look around the area for more information about what is causing the contamination

Take immediate action if you notice evidence of a petroleum leak at or near your location.

The owner or operator must notify the state or local implementing agency within 24 hours of a suspected underground storage tank release. They should also immediately stop the release and ensure that people nearby are not in danger.

Tanks used to store heating oil on the same property are not regulated by the federal government. However, state or local governments may have rules about these tanks. Regulatory agencies in your state or locality can provide more information.

The state or local government also regulates Aboveground Storage Tanks (AST). It protects people and the environment from any potential dangers that ASTs might pose. Check with the state agency responsible for oil pollution control to find out what the requirements are in your state.

Rob Paredes
Article by
Rob Paredes
SafetyCulture Content Contributor
Rob Paredes is a content contributor for SafetyCulture. Before joining SafetyCulture, he worked as a financial advisor, a freelance copywriter, and a Network Engineer for more than a decade. Rob's diverse professional background allows him to provide well-rounded, engaging content that can help businesses transform the way they work.