UST Map

Petroleum Contamination

Environmental pollution caused by the release of petroleum products such as gasoline, diesel, and heating oil from UST systems.

Petroleum contamination from underground storage tank systems is the most common form of soil and groundwater pollution in the United States. Gasoline, diesel fuel, heating oil, and other petroleum products stored in USTs can leak into the environment through corroded tanks, failed piping connections, or operational spills, creating contamination that may persist for decades.

The behavior of petroleum contamination in the subsurface depends on the product type, soil characteristics, and hydrogeological conditions. Light non-aqueous phase liquids (LNAPLs) like gasoline float on the water table, while dissolved-phase contaminants spread through groundwater. Vapor-phase contamination can also migrate into buildings, creating indoor air quality concerns.

Cleanup of petroleum contamination at LUST sites follows a systematic process: initial response and free product removal, site characterization, corrective action planning, active remediation, and long-term monitoring. The total number of petroleum-related LUST releases in the US exceeds 510,000, with ongoing cleanup efforts at tens of thousands of sites nationwide.

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