El Toro Marine Corps Air Station

Overview

El Toro Marine Corps Air Station is a former military facility covering about 4,700 acres in Orange County, California. It operated as a major west coast jet fighter base starting in 1943 and closed in 1999 under the Base Realignment and Closure Act. The EPA added it to the Superfund National Priorities List in February 1990. The Navy leads cleanup under the Installation Restoration Program, a Department of Defense program created in 1978 to address hazardous contamination at military sites.

More than 100 chemical substances have been identified as contaminants of concern. These include volatile organic compounds (VOCs) such as trichloroethene, tetrachloroethene, and benzene, which are found mainly in groundwater and at a soil source area near Site 24. Metals like arsenic, beryllium, and manganese appear primarily in soil at burn pits and landfills. Polychlorinated biphenyls (PCBs), pesticides including DDT and dieldrin, and perchlorate from an old explosive ordnance disposal range are also present. No drinking water sources have been contaminated, and the Upper Newport Bay Ecological Reserve may be threatened by site contaminants.

Cleanup is organized into nine operable units covering groundwater, soil, landfills, burn pits, and an ordnance disposal range. Several units have finished active work. Groundwater remediation moved into operation and maintenance in March 2008. Soil cleanup at multiple sites wrapped up between 2002 and 2013. Landfill units completed remedial action between 2009 and 2013. A groundwater extraction and treatment system has been fully operational since 2006 and continues running. Work on the EOD Range (Operable Unit 8) is still ongoing, with final remedy selection estimated between September and November 2026 and final remedial action starting between September and November 2027.

The EPA has determined that human exposure is under control across the entire site, meaning no unacceptable pathways for people to contact contamination currently exist. Groundwater migration is also under control. Physical construction is not yet complete, and the site is not sitewide ready for anticipated use. The most recent five-year review was completed on September 26, 2024. The site anticipates achieving sitewide readiness for reuse between March and May 2026. Redevelopment is already underway, with 2,800 acres sold and transferred in part to Heritage Fields LLC and a golf course parcel transferred under the Land for Parks program.

Community members with questions can contact the EPA's Community Involvement Coordinator or the Remedial Project Manager. Additional records are maintained through the Navy Base Realignment and Closure Program Management Office and the California Department of Toxic Substances Control.