Underground Storage Tank Hazards

According to the U.S. Environmental Protection Agency (EPA), there are about 625,000 underground storage tanks (UST) nationwide that store petroleum or other hazardous substances. If these tanks are compromised, they could leak their contents into the ground, creating contamination that may damage the environment and pose a hazard to human health.

In its FY 2007 Annual Report on the Undground Storage Tank Program, the EPA outlines what is being done in conjunction with states, tribes and other partners to prevent, detect and clean up petroleum leaks from underground storage tanks. Such measures are mandated by the Energy Policy Act of 2005.

At particular risk of contamination from leaking USTs is groundwater supply. According to the Sierra Club, studies indicate USTs that hold gasoline, oil or other toxic materials risk leaking contaminants such as benzene, toluene and heavy metals that may cause cancer and harm children.

According to the Sierra Club’s report, released in 2004, chemicals in USTs can quickly move through soil and pollute groundwater. The report indicates that one gallon of petroleum can contaminate one million gallons of water, and that one pin-prick size hole in an UST can leak 400 gallons of fuel per year.

The EPA sets standards under the Safe Drinking Water Act for approximately 90 contaminants in drinking water. The EPA sets a legal limit, called the maximum contaminant level, for each of these contaminants.

Ground water is defined as the water that systems pump and treat from aquifers (natural reservoirs below the earth’s surface). The Sierra Club estimates 50 percent of the nation’s population and 100 percent in virtually all rural areas rely on groundwater for drinking water.