Concord Naval Weapons Station is a 12,800-acre former military base in Contra Costa County, California. The Navy established it in 1942 to load and unload weapons and equipment from ships. It was added to the National Priorities List in 1994, and active cleanup work began in 2005. The site splits into two main zones: the Inland Area, still under Navy cleanup, and the Tidal Area, transferred to the Army in 2008. A small radiography facility in Pittsburgh is also part of the site.
Contaminants found here include heavy metals such as arsenic, lead, mercury, and cadmium in soil and sediment. Chlorinated solvents, including trichloroethene and tetrachloroethene, appear in groundwater and soil gas. Polychlorinated biphenyls, dioxins, and other organic compounds are present as well. Unexploded ordnance is a concern at two locations. Groundwater is contaminated above drinking water standards. Wetland species, including the Salt Marsh Harvest Mouse and California Clapper Rail, face ecological risk.
The Navy is the lead agency for cleanup, with EPA serving as the lead regulatory authority. Cleanup actions already completed include a soil cap placed over the Tidal Area Landfill in 2004, soil excavation and wetlands restoration at the Litigation Area, and removal of munitions and metals from the Inland Burn Area and Pistol Firing Range. Ongoing work includes groundwater treatment, soil vapor extraction, and additional site investigations. Current assessments show human exposure is under control, meaning no unacceptable exposure pathways exist right now. However, whether contaminated groundwater movement has stabilized is still uncertain due to limited data. Physical cleanup is not yet complete, and the site is not ready for its full anticipated use. Several operable units still need formal cleanup decisions, with some remedy decisions estimated between 2027 and 2028.
Portions of the former station have already been transferred for reuse. About 1,235 acres went to the City of Concord for residential and commercial redevelopment, and 2,288 acres went to the East Bay Regional Parks Department. The City selected Lennar Concord LLC as the master developer for the first phase. The Tidal Area is not planned for transfer or redevelopment in the foreseeable future.
Community members can take part through the Navy's Concord Restoration Advisory Board, which meets on the second Wednesday of January, April, July, and October. Meetings run from 6:00 a.m. to 8:00 p.m. and are open to the public. The board is currently accepting membership applications. Meetings are held at the Clyde Clubhouse, 109 Wellington Avenue, Clyde, California 94520. Environmental documents are available at the Concord Public Library at 2900 Salvio Street, Concord, CA 94519. EPA staff can also answer questions directly.
