Former MCAS Tustin was extensively used for agriculture prior to being commissioned in 1942 for a lighter-than-air patrol base and re-commissioned in 1951 to support helicopter operations. Physical improvements installed over the years to support the mission of MCAS Tustin included: approximately 200 buildings and structures; a 3,000-foot runway, aircraft parking aprons; and aircraft maintenance shops. Support facilities, including military housing, occupied approximately 1,100 acres of the approximately 1,500 acres of the former MCAS Tustin. The remaining approximately 400 acres of the former MCAS Tustin was undeveloped and leased for commercial agricultural use.
During the operation of former MCAS Tustin, certain contaminants were released into the soil and groundwater primarily resulting from, but not limited to, solvents and jet fuel supporting the base operations, and from pesticides associated with the agricultural uses. Since the initiation of the “Navy Assessment and Control of Installation Pollutants Program” in 1980 (which later became the current Installation Restoration Program (IRP)), the Navy has successfully completed numerous site investigations and remedial actions; however, contaminated groundwater plumes remain. The chemicals of concern (COC) remaining in the groundwater are generally a result of fuel and solvents previously used in the operation of former MCAS Tustin.
Remediation continues to be undertaken by the Department of the Navy under oversight of the U.S. Environmental Protection Agency (EPA), and the California EPA (Department of Substances Control (DTSC) and Regional Water Quality Control Board (RWQCB)).