McClellan Air Force Base (Ground Water Contamination)

Overview

McClellan Air Force Base is a former military logistics facility in Sacramento, California that operated from 1936 until 2001. Aircraft maintenance and repair activities left behind contamination across 3,452 acres, with the Air Force identifying 326 waste areas containing hazardous materials. The site was added to the EPA's National Priorities List in July 1987 and remains on that list today.

Contaminants include volatile organic compounds (VOCs) such as trichloroethene, tetrachloroethene, benzene, and toluene in groundwater and soil. Chlorinated solvents, heavy metals like lead and chromium, pesticides including DDT and chlordane, polychlorinated biphenyls (PCBs), petroleum hydrocarbons, polycyclic aromatic hydrocarbons, radioactive substances, and dioxins are also present across soil, groundwater, sediment, and soil gas. People could be exposed through contact with contaminated soil or groundwater, inhaling dust or vapors, or eating food with accumulated contaminants. Wildlife and nearby creeks, vernal pools, and floodplain habitat may also be affected.

The Air Force Real Property Agency leads cleanup under EPA Region 9 oversight, working alongside the California Department of Toxic Substances Control and the California Regional Water Quality Control Board. A Federal Facilities Agreement has been in place since 1990. The restoration program has spent roughly 533 million dollars, with another 94 million dollars anticipated. Sixteen Records of Decision have been signed. An 85-well groundwater extraction system pulls about 1,450 gallons per minute of contaminated water and has removed more than 61,000 pounds of contaminants. A soil vapor extraction program has removed approximately 1.7 million pounds of contaminants from the soil. An engineered containment unit the size of seven football fields, built five stories deep, permanently stores up to 360,000 cubic yards of contaminated soil and waste on-site.

EPA assessments show human exposure is currently under control, with no unacceptable exposure pathways at present. Groundwater contamination is stabilized and not discharging unacceptably to surface water. Construction across the site is estimated to be complete between December 2027 and February 2028. The pump and treat groundwater system is expected to run for approximately another 30 years.

Community members can stay involved through public meetings held four to eight times per year at locations surrounding the former base. The Restoration Advisory Board, made up of community members, meets quarterly and advises the Air Force and government representatives on cleanup and future land use. The board accepts both invited and unsolicited recommendations from residents.