Leaking Underground Fuel Tanks

The most common type of contamination comes from leaking underground fuel tanks and piping systems. Underground tanks are common throughout California as well as throughout the United States. These tanks are predominantly used for storing fuel, although solvents used in high technology industries and other substances are stored in this manner also.

Why underground tanks? Many years ago, jurisdictions developed regulations with regards to fuel tanks for the “esthetic” protection of growing cities as well as providing important fire safety measures. For these reasons, the majority of fuel tanks must be buried. Unfortunately, the state building codes that regulate underground fuel tank construction did not keep up with changing technology. The result was that industry used traditional methods in building underground tanks and pipes. Today, there are laws in place that ensure strict building codes are followed in new tank construction, as well as upgrades for all substandard underground tanks.

When an underground tank leaks, the soil and/or groundwater can become contaminated. How much fuel actually gets into the soil depends on how big the leak is and how long the leak continues. Experience shows that leaking fuel “seeps” into the ground at a generally slow rate and usually does not travel very far. “Seeping” fuel into the soil can be likened to wetting the corner of a sponge. With only a small amount of water, only the corner gets wet and the rest of the sponge remains dry.

If a leaking underground fuel tank is discovered, the tank owner or responsible party must notify the appropriate Regional Water Quality Control Board (RWQCB) or county-level agency and submit an “unauthorized release form”. The responsible party must also make every effort to stop the leak and empty the tank if necessary. The RWQCB or county-level agency will then undertake the lead in clean-up efforts, with the tank owner or responsible party reporting directly to them. Until investigation and cleanup are complete, the tank owner or responsible party must submit reports detailing cleanup efforts to the lead agency at least every three months. If the investigation fails to confirm that a leak has actually occurred, no further corrective action will be required. For those Sites that do require corrective action, the cleanup process could take a few months to many years, depending on the severity of the leak. Additional information may be available through the Public Safety Officer or Hazardous Materials Specialist in the city who is often within the Fire Department or Public Works Department.