Cost of a leaking UST cleanup

Do you have a leaking underground storage tank? Ambipar Response EMS has managed hundreds of leaking underground storage tank cleanup projects over the last 25 years. We have frequently answered the same great question that you have: “How much will a leaking underground storage tank cleanup cost me?” Truth is, there is no singular answer for this question because costs for cleanup and assessments may range from $100 to tens of millions of dollars based upon the various aspects of each situation. In this article, we will present the factors that determine cleanup costs and will provide you with the average costs our clients have experienced.

Leaking Underground Storage Tank Cleanup Process

Tanks may contain a wide variety of liquids ranging from non-hazardous to extremely hazardous substances. Since gasoline is the most common material that is stored in underground storage tanks (UST), we will limit our examples to spills from gasoline storage tank and dispensing systems.

Low cleanup cost scenarios are relatively common. An example of a low-cost cleanup would be a small surface spill that can be cleaned up by spreading absorbent material on the spill and disposing of the absorbent material when dry. In many cases, this type of spill is not a reportable event and the project is completed after cleaning up the material. Different states have different thresholds where spills must be reported. In some states, the threshold is less than 25 gallons (of gasoline) while in other states any quantity must be reported to the regulatory agency. When there is a reportable event, there is always the expense of a written report to the agency.

High cleanup cost scenarios are very rare. An example of a high-cost cleanup would be a very large spill that caused third-party damages such as impact to public water supplies, release to surface waters, explosive conditions in neighboring buildings, loss of business, health impacts, fines, and legal costs.

Some states even have cleanup cost reimbursement programs for spills where, after reaching a deductible, most cleanup costs are paid from a gasoline tax fund. There are also insurance products that cover leaking UST (LUST) claims.

Report the Spill

Once the owner/operator is aware of a spill, it must be reported to the state regulatory agency hotline. The spill could be discovered via inventory discrepancy, discovery of gasoline product in a well, gasoline odors in a building or utilities, discovery of gasoline contaminated soil, etc. The call to the spill hotline can be made by the owner, an environmental consultant, a contractor, or anyone with knowledge of the spill. Based upon conditions, immediate cleanup measures may have to be taken. These cleanup measures may include employing vacuum trucks to extract free product from tank field wells, sumps or excavations, deployment of boom on waterways, or venting of explosive vapors from underground utilities. The state regulatory agency will then require a written report detailing the spill and any initial cleanup efforts that were conducted.

Environmental Assessment

The regulatory agency will require an investigation to determine the extent of the impact of the spill. The various state agencies use different names for the assessment or investigation process but they all have similar requirements and objectives. Most assessments begin with installation of soil borings and monitoring wells to identify the extent of contamination. Hydrogeologists use this information to determine the direction of flow and the predicted extent of impact over time. Larger and/or more extensive spills will require a more extensive monitoring well network be installed to fully define and characterize the extent of contamination. Additional tests—such as a geophysical investigation—may have to be conducted to look for unknown underground tanks, or an aquifer test may be used to define soil and groundwater properties. The experience of the environmental professional will have a big impact on the necessity and complexity of the testing.

Remedial Action Plan

Once the regulatory agency approves the environmental assessment, they will require a Remedial Action Plan (RAP). There is a wide range of technologies and techniques that can be employed as cleanup measures, which also results in a wide range of costs. There are also regulatory factors to consider, such as risk-based cleanups (not allowed in all states) and cleanup measures that take many years to complete, versus relatively quick (and expensive) methods that are conducted over a much shorter period of time.

Remedial Action Implementation

The implementation phase begins after regulatory agency approval of the Remedial Action Plan. This is the point where all of the designs from the RAP are implemented, any required permits are obtained, and ongoing sampling and monitoring activities are conducted.

Regulatory Closure

The results of the ongoing sampling and monitoring results will indicate when remedial activities can cease and the regulatory agency will grant closure status to the spill. This process usually involves a final report and there may be land covenant issues or other ongoing requirements to address, but in the end the owner/operator will get a letter from the agency indicating no further action is required.

Environmental Factors that Affect Leaking Underground Storage Tank Cleanup Cost

Environmental factors have a big influence on the leaking underground storage tank cleanup cost. These factors include:

Type of product lost
Volume of product that was lost or spilled
Time period over which the leak occurred
The geology
Proximity to buildings
Proximity to private water supply wells
Proximity to public water supply wells
Proximity to underground utilities
Proximity to surface water bodies

Type of Product Lost

Since we are limiting our focus to gasoline, we will review the components of gasoline. Gasoline is made up of hundreds of different chemical compounds. Some of those compounds are hazardous because of the potential to accumulate explosive vapors and other compounds are hazardous because they can contaminate drinking water. Benzene, for example, is a carcinogenic component of gasoline. According to the Environmental Protection Agency, the safe drinking water limit for benzene is 5 micrograms per liter (same as parts per billion if we were dealing with a solid). In some states, the limit is only 1 microgram/liter. Although Benzene makes up less than 1% of the volume of gasoline, a 10 gallon gasoline leak can potentially contaminate 12 million gallons of water. At those levels, it does not take much of a release to prompt regulatory action.

Volume of product that was lost or spilled

This factor is self-explanatory. It is a lot easier to clean up a five-gallon spill than a 50,000-gallon spill.

Time period over which the leak occurred

The longer the time period a leak has occurred, the greater the chance that the leak has spread over a large area. Leaks that have spread over a great distance require more monitoring wells to characterize the extent of the plume, more ongoing sampling, and higher remediation costs.

Geology

The subsurface geology controls the direction and rate of groundwater (and contaminant) flow. Sites with a great soil thickness above the water table may contain the spill in the soil matrix on site. Alternatively, if the water table is shallow, water supplies could be impacted relatively quickly. The type of soil and rock material also determines the rate and extent of contaminant transport.

For example, clay inhibits groundwater flow whereas groundwater flows quite rapidly through sandy soil. Different types of bedrock have similar qualities where flow is rapid though the cracks and fractures in some types of rock and relatively slow in other types of rock that have an absence of cracks and fractures.

Different soil and rock types require different technologies for installation of monitoring wells. Of course, deeper wells (if the water table is far from the surface) are much more expensive to install than shallow wells, and bedrock wells are much more expensive to install than wells installed in sand.

Proximity to public and private water supply wells

Contamination of wells that supply potable water to a network of users is never a good thing! Even if the spill does not impact the public supply well, extraordinary cleanup measures may have to be taken to rapidly clean up the spill so that contamination is contained and does not have a chance to spread to this sensitive receptor. If the private well is impacted, a water treatment system will have to be installed or an alternative supply provided.

Proximity to buildings

Close proximity to buildings presents an opportunity for accumulation of explosive vapors and/or impact to indoor air quality. Most states have started to require air quality testing when contaminant plumes approach the vicinity of a building.

Proximity to underground utilities

Close proximity to underground utilities presents an opportunity for accumulation of explosive vapors. In older areas of the country, there have been occasions where vapors from impacted sewers and storm drains have migrated into buildings and caused evacuations.

Proximity to surface water bodies

If a spill runs into surface water, an additional hotline call may have to be made to the U.S. Coast Guard. This occasion would necessitate the immediate deployment of boom to prevent migration of the spill and damage to shorelines and aquatic life.

What is the Leaking UST Cleanup Going to Cost Me?

We assembled data from over 300 leaking underground storage tank projects conducted by EMS over the last 25 years to formulate the following costs. Projects where spills were not reportable and projects that involved litigation costs were not considered, as we do not have access to those costs. Estimated cost to closure data were used for projects that had not yet reached regulatory closure status.

Cleanup costs at these sites ranged from $1,000 to over $2,000,000. The average cleanup cost was approximately $275,000 and the median cost was $225,000. No two sites were ever the same and no cleanup technology was best for every circumstance. If you have a leaking underground storage tank, and you want to minimize cleanup costs, engage a consultant with a wide range of UST cleanup experience who does not have to reinvent cleanup strategies, and who also has familiarity with regional regulatory personnel.

If you believe you have a leaking underground storage tank, be sure to report the spill immediately. EMS has reviewed a lot of factors that go into the cost of a cleanup. An experienced consultant can help you navigate the best way through the process.