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Underground Storage Tanks: Risks and the Removal Process (Infographic)

underground storage tank removal

Are you familiar with underground storage tanks (USTs)? If you own property or work in real estate, you should be. If improperly maintained, disposed of, or registered, they pose a serious environmental liability. And with approximately 542,000 USTs across the U.S., they may be more common than you think.

A UST is a tank with at least 10% of its combined volume below ground. While USTs can hold a variety of compounds, the ones that present an environmental risk are used for petroleum or hazardous substances. These USTs are typically regulated by local or state agencies, like the Indiana Department of Environmental Management in Indiana.

One of the most common places USTs are found is gas stations. It’s not uncommon for a gas station to have four or five USTs on their property. They are used to store fuel, which then runs through underground piping to dispensers that we use to fill our cars. This whole system is known as an underground storage tank system. Beyond gas stations, there are a variety of other facilities that may have underground storage tanks for petroleum compounds – really any facility that uses large quantities of petroleum products. This ranges from vehicle maintenance garages to fleet vehicle yards and even agricultural facilities.

On the other hand, USTs used to store hazardous substances are less common, but still exist. Any business that utilizes large quantities of hazardous substances in its operation may have one onsite. USTs provide an out-of-the-way place to store excess liquid products. Hazardous substance USTs are most commonly found at industrial manufacturing facilities.

Risks Associated with USTs

It is important to know if a UST is on your property because it can carry significant environmental risks. A leaking UST can spread regulated substances (contamination) across a large, and possibly deep area, making it difficult to define and expensive to clean up.

Because USTs are underground, it is challenging to identify leaks. This is particularly true with older USTs that may not meet current standards or have been neglected. Further, depending on the soil, USTs can corrode, degrading their integrity.

Another consideration is the many connections and components in a UST system. Not only is there just a UST to think about, but also pipes and dispensers. Any small leak in the system, particularly if it is not caught for an extended period of time, can lead to a significant release.

In many cases, contamination released by a UST is not identified until the UST is being removed. This is a challenging process to deal with and if it happens during redevelopment, it will undoubtedly delay work. Taking preemptive measures to identify and assess onsite USTs is crucial in mitigating risk, preparing for redevelopment, and assessing property value.

UST Services Provided by Aegis

The UST identification, assessment, and removal process can be quite complicated. There are typically several government agencies, permits, and protocols involved. That is why Aegis Environmental provides full turn-key solutions for UST management.

While we do assess each project individually, there is often significant overlap. A few of these key components include:

    • Preliminary investigation and remediation planning
    • Notifying state and federal regulatory agencies
    • UST removal, decommissioning and cleaning
    • Soil and groundwater assessment
    • Demolition services
    • UST removal report
    • UST reimbursement fund submittal

Even though we provide all of the necessary services to manage a UST removal, it is useful for the responsible party to understand what the process looks like. This helps set expectations and recognize the necessity of managing USTs with the correct framework.

Preliminary Services

The initial step in UST removal is a preliminary investigation. This investigation takes two forms – research and sampling. First, research of government records and historical information (like historical aerial photographs) will help locate a UST if its specific location on a property is unknown. If at this point the tank’s location still cannot be identified, it is prudent to implement a geophysical UST survey. A geophysical survey utilizes ground penetration radar (GPR) and other specialized instruments to locate the metal UST and associated piping.

Next up is soil sampling. Sampling before UST removal activities provides initial data on any compounds that may have been leaking from the tank. This data is used in the second portion of the preliminary work – remediation planning.

Developing an initial remediation plan streamlines the removal process. It provides a guideline for remediating any expected contamination when the UST is initially removed. Developing this plan before the UST is removed allows for the correct equipment and personnel to be ready onsite, limiting downtime.

Finally, before “digging in” the appropriate government agency that oversees UST removal activities will be notified. In many cases, a representative from the agency will be present onsite while the UST is removed to ensure the correct procedures are followed.

UST Removal Process

Ideally, there is an access point to the UST at the ground surface. In this case, all product left in the UST is removed using a vacuum truck. Next, the UST is purged of vapors. UST contents are often flammable (like gasoline), so removing the vapors eliminates the possibility of an explosion during removal activities.

From here, earth-moving equipment is used to expose the top and sides of the UST, along with any underground piping and dispensers. At this stage, each UST removal becomes unique depending on the contents, type of UST system (quantity of piping, dispensers, etc.), and regulatory agency involved. But in general terms, the entire UST system is removed, cleaned, and taken offsite for disposal or recycling.

Visibly contaminated soil is removed from the excavation and stockpiled. It is then segregated, characterized, and disposed of at the appropriate offsite facility.

Verification Sampling

Verification soil samples are collected to confirm that the contents stored in the tank are not present in the soil left in place. The number and location of samples are different for each state, but generally, samples from beneath the UST system (tank, dispensers, and product piping) and from the sidewalls of the excavation are required. If groundwater is encountered this will also need to be sampled. Again, analysis of the samples is dictated by the tank’s contents and oversight agency’s requirements, but typically these include volatile organic compounds (VOCs), metals, and other petroleum constituents.

If the samples contain contaminant concentrations above regulatory limits additional subsurface sampling and remedial activities will likely be deemed necessary.

UST Closure Report

Finally, the UST removal activities are described in a closure report submitted to the relevant oversight agency. Specific reporting requirements vary by state, but in general, closure reports include:

Description of the removal activities
Documentation of the soil/UST disposal
Analytical information on samples collected
Maps identifying the location of the UST system, excavations, and samples
If the UST removal and remediation meets agency requirements, they will issue a “No Further Action” letter. This designation means the UST has been adequately removed and the agency does not consider it a risk to human health or the environment. This is crucial in limiting your liability and protecting the value of the property.

What Are the Next Steps?

It is a daunting reality if you find a leaking UST on your property. Not only can the removal and remediation process be time-consuming, but it is often quite expensive. Luckily, most states have a reimbursement fund to assist UST owners in funding cleanup activities.

At Aegis Environmental, we are experts in the UST management process. We have completed hundreds of successful UST investigations, cleanups, and closures. With our full range of UST-related services, we take care of a project from start to finish, including submitting UST reimbursement claims to state agencies.

If you have an unused UST on your property or think that you might have one,  contact us. One of our environmental professionals is ready to help you assess the situation and determine your options moving forward.

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April 12, 2022
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January 28, 2022
Fantastic company to work with. I'm under contract to buy a home and an underground storage tank was discovered by my home inspector. After a call with Aegis, they were able to get out to the property quickly to assess the problem. Turns out, there are FOUR underground storage tanks present since the property is multi-family. They have been very thorough, professional, and communicative to work with so far. I highly recommend working with them for any/all of your environmental remediation/cleanup needs.
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December 1, 2021
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