Sharpe Army Depot is a 724-acre former Defense Logistics Agency facility near Lathrop, California. It operated from 1941 to 1975, leaving behind contaminated soil and groundwater from maintenance and disposal of aircraft, vehicles, and industrial and medical equipment. The site was added to the National Priorities List (NPL) in 1987 and operates under a Federal Facilities Agreement involving the Army, EPA, state agencies, and regional water quality authorities.
The main contaminants in groundwater include volatile organic compounds (VOCs) such as trichloroethene, vinyl chloride, benzene, and chlorinated solvents including carbon tetrachloride and dichloromethane. Soil contains those same VOCs plus metals like arsenic, cadmium, chromium, lead, nickel, and beryllium, along with pesticides including DDT and dieldrin, and polycyclic aromatic compounds. Trichloroethene was also detected in soil gas across the site.
Past cleanup work included excavating metals-contaminated soils, running soil vapor extraction for VOCs from 1998 to 2001, and treating groundwater with air stripping and carbon adsorption starting in 1987. A second groundwater treatment system came online in the North Balloon area in 1990. Cleanup construction wrapped up in 2003. EPA's August 2020 five-year review found that the remedies protect human health and the environment in the short term, but flagged needs for additional monitoring wells, new extraction wells, and further evaluation of lead and hexavalent chromium. The most recent five-year review was completed on September 30, 2024. Human exposure is not currently under control and groundwater migration is not stabilized, meaning contaminated groundwater is still spreading beyond the original area.
In May 2022, the Army confirmed the presence of per- and polyfluoroalkyl substances (PFAS) in on-site soils and groundwater. A Remedial Investigation for PFAS began in July 2023 and is ongoing. Feasibility studies for some soil contamination areas are estimated to finish between 2027 and 2028. The site has not been deleted from the NPL and has not achieved sitewide ready-for-anticipated-reuse status. Institutional controls, including a ban on residential use, are in place. The Army is leasing portions of the site to federal entities and is working toward transferring some property outside federal government control.
Community members can get involved by contacting the Army's Restoration Project Manager, Mark Eldridge, or EPA's Community Involvement Coordinator, David Yogi. Site documents are available at the public Information Repository at 700 E. Roth Road in French Camp, California, by appointment, and online through California's GeoTracker and EnviroStor databases. The Army completed a Community Relations Plan Update in February 2023 and will notify the public of new documents through local newspaper notices.
