Underground storage tank

USTs are regulated in the United States by the U.S. Environmental Protection Agency to prevent the leaking of petroleum or other hazardous substances and the resulting contamination of groundwater and soil.

[3] In September 1988, the EPA published initial underground storage tank regulations, including a 10-year phase-in period that required all operators to upgrade their USTs with spill prevention and leak detection equipment.

The revisions will also help ensure all USTs in the United States, including those in Indian country, meet the same minimum standards.

Many have leaked, allowing petroleum to contaminate the soil and groundwater and enter as vapor into buildings, ending up as brownfields or Superfund sites.

[citation needed] Many USTs installed before 1980 consisted of bare steel pipes, which corrode over time.

[7] The 1984 Hazardous and Solid Waste Amendments to the Resource Conservation and Recovery Act (RCRA) required EPA to develop regulations for the underground storage of motor fuels to minimize and prevent environmental damage, by mandating owners and operators of UST systems to verify, maintain, and clean up sites damaged by petroleum contamination.

[8] In December 1988, EPA regulations asking owners to locate, remove, upgrade, or replace underground storage tanks became effective.

The national inventory of underground tanks has been reduced by more than half, and most of the rest have been replaced or upgraded to much safer standards.

[citation needed] Of the approximately one million underground storage tanks sites in the United States as of 2008, most of which handled some type of fuel, an estimated 500,000 have had leaks.