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Underground Storage Tanks
What is an Underground Storage Tank and what is it used for?
Underground Storage Tanks (UST’s) are tanks containing fuel, typically for home heating purposes, that are buried in the ground. While the EPA does not regulate residential UST’s used for home heating if stored on the premises where used, they do define a UST as any tank and any underground piping connected to the tank that has at least 10 percent of it’s combined volume underground. While not regulated by the EPA, there may be local or state regulations.
Why be concerned about UST’s?
Until the mid-1980’s, most UST’s were made of bare steel, which is likely to corrode over time and allow UST contents to leak into the environment. The average life expectancy of a buried tank is 15 years. The greatest potential hazard from a leaking UST is that the petroleum or other hazardous substance can seep into the soil and contaminate groundwater. A leaking UST can also present other health and environmental risks including the potential for fire and explosion.
How is the UST tested and are there specific requirements?
Testing methods can vary by area and state and/or local requirements. Testing methods can include one or more of the following:
PRESSURE TESTING - Oil Tank Pressure Testing Advice
Using this tank testing method the oil tank is sealed and pressurized to a low psi level, then carefully monitored for a pressure drop, perhaps for 24 hours. This method is comparatively quick to execute but has its limitations.
- First, if there is a pressure drop, additional testing will be required to determine if there has been actual oil seepage into the soil. (A leak could have been a minor one at the tank top, for example.) The additional testing is much the same as the method described below under soil testing.
- Second, even if there is no pressure drop, there still is no guarantee that there hasn't been a tank leak in the past, perhaps fixed by a plumbing repair or other method.
Some homeowners balk at this test, fearing that the pressure of the test procedure will "burst" an oil tank that is about to fail. The pressure at which the tank is being tested is almost certainly a much lower psi than the pressure to which the tank is subjected while it is being filled by the oil delivery truck.
SOIL TESTING - Soil Tests for evidence of tank leakage
This method may cost about the same as the first method. Multiple soil borings are collected around the tank, at a depth just past the level of the tank bottom. The soil samples are tested for petroleum product contamination.
This is considered the definitive test for oil tank leakage and if the tank has not leaked, it provides more reliable documentation of that fact. More time is needed to complete the test as there is a delay for the lab work.
What if a leak is discovered?
The first thing to do is contact your local Department of Environmental Health or Health Department to determine if there are any required procedures. In many instances the fuel supply company can assist with the process. Clean up procedures can vary depending on local requirements and the amount of leakage that has occurred.
Abandoned and/or removed tanks.
If told that an oil tank has been "removed" or "abandoned" at a property, then expect to be given the documentation that outlines who did what when and more importantly, what steps were taken to assure that no oil leak was simply left for the next owner to discover and clean up. The documentation should also verify whether any state and/or other local requirements have been met. If adequate documentation is not provided, a soil test is certainly appropriate.