What Is the Problem With Underground Storage Tanks?

By U.S. law, an underground storage tank (UST) is defined as any tank and any underground piping connected to the tank which has ten percent or more of its total volume underground and holds more than 1,100 gallons. According to the U.S. Environmental Protection Agency (EPA), there are 607,000 USTs in the United States which contain petroleum or other hazardous substances.

Leaky Underground Storage Tanks

• Underground storage tanks, mostly at gas stations, are a major contributor to groundwater pollution in the United States. Many of the leaky tanks were installed before 1980 and used bare steel piping, which corrodes over time. Petroleum contamination of soil and groundwater can damage soil fertility and increase the risks of cancer and other diseases.

Legislation

• Leaky USTs fall under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), also known as Superfund. This act holds owners of USTs responsible for any cleanup costs associated with leaks, even if they bought the land without knowing that it contained leaky tanks. The Resource Conservation and Recovery Act (RCRA) also created a special program for the monitoring, repair, removal or replacement of USTs. The EPA's Underground Storage Tank Program has been mostly successful in removing or upgrading tanks.

Remedies

• Modern USTs use corrosion resistant materials such as fiberglass. Many are double-walled, so that even if the inner wall leaks, the chemicals will not be released into the environment. This second chamber is usually outfitted with leak sensors that detect if a leak has occurred.