Marine Corps Air Station El Toro

Marine Corps Air Station El Toro was a 4,700-acre Marine Corps installation in Orange County, California, near the city of Irvine. Commissioned in 1943, the air station supported Fleet Marine Forces operating in the Pacific during World War II and was designated a permanent Master Jet Station in 1950. In 1955 it became home to the 3rd Marine Aircraft Wing and served for decades as the major west coast jet fighter facility for the Marine Corps. The station was designated for closure by the Base Realignment and Closure (BRAC) Commission in 1993 and officially closed on July 2, 1999, with its aviation activities transferred to Marine Corps Air Station Miramar. Much of the former base has since been redeveloped, including as the Orange County Great Park.

There are concerns about carcinogenic health hazards at the former MCAS El Toro, due to potential exposure to various environmental contaminants found in soil and groundwater at the base:

1. TCE (trichloroethylene): TCE is a chlorinated solvent that was widely used at El Toro to degrease and wash down aircraft, with two large aircraft hangars identified as a primary source area. The chemical was discovered in groundwater beneath the base in 1985, and the resulting plume migrated roughly three miles off base into Orange County's aquifer, reaching depths of several hundred feet in some areas. Exposure to TCE has been associated with an increased risk of certain cancers, including kidney cancer, as well as other health effects.
2. PCBs (polychlorinated biphenyls): PCBs are industrial chemicals once common in electrical equipment, and they were among the hazardous substances suspected of being dumped or spilled at sites across the station. PCB-contaminated soil was excavated at one El Toro site, with that work completed in 2005. PCBs are classified as probable human carcinogens, and exposure may potentially be linked to cancer and immune, reproductive, and nervous system effects.
3. Industrial solvents and other VOCs: In addition to TCE, a range of volatile organic compounds from degreasing, paint stripping, and aircraft cleaning operations was identified in soil and groundwater at the base. Long-term exposure to certain VOCs has been associated with potential harm to the liver, kidneys, and central nervous system, and some are considered known or suspected carcinogens.
4. Jet fuel and leaded fuels: Decades of fueling and aircraft maintenance left petroleum hydrocarbons in soil and groundwater, and leaded fuels and battery acids were suspected of being disposed of at several areas on the station. Components of jet fuel, such as benzene, have been associated with blood disorders and an elevated risk of leukemia and other cancers.

The EPA placed El Toro Marine Corps Air Station on the Superfund National Priorities List in 1990, identifying 25 potentially contaminated areas, including four landfills. Cleanup has been organized into multiple operable units, and a large groundwater extraction and treatment project, operated in partnership among the Navy, the Irvine Ranch Water District, and the Orange County Water District, reached full operation in January 2007. Treated water is used only for non-drinking purposes, and cleanup of the off-base TCE plume is expected to take approximately 40 years.

While there are concerns about potential exposure to these contaminants among those who lived or worked at MCAS El Toro, establishing definitive links between specific exposures and individual health conditions can be complex. Research into the long-term effects of these substances is ongoing. Veterans and family members who spent time at El Toro are encouraged to stay informed about the site's cleanup, document their service history, and consult the Department of Veterans Affairs about health concerns and any benefits for which they may be eligible.