The Aerojet General Corp. site spans about 5,900 acres near Rancho Cordova, roughly 15 miles east of Sacramento. Since 1953, the facility has been used to research, design, and manufacture rocket engines and formulate chemicals. Disposal and operating practices led to widespread soil and groundwater contamination. EPA added the site to the National Priorities List (NPL) in 1983. The site's northeastern edge sits about half a mile from the American River.
EPA has identified more than 140 contaminants of concern across soil, groundwater, and soil gas. These include volatile organic compounds such as trichloroethene and tetrachloroethene, heavy metals including lead, mercury, cadmium, chromium, and nickel, polychlorinated biphenyls (PCBs), pesticides including DDT, petroleum hydrocarbons, and groundwater contaminants such as 1,4-dioxane, perchlorate, and N-nitrosodimethylamine. The chemical 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was also found in soil. EPA determined these substances pose an unacceptable risk to human health or the environment.
Aerojet General Corporation and Cordova Chemical Company are the potentially responsible parties. Ten groundwater extraction and treatment systems operate across the site, removing over 20 million gallons of contaminated groundwater daily on average. Through the end of 2010, those systems had treated a cumulative 107,000 million gallons and removed more than 850,000 pounds of chemical contaminants. The site is divided into multiple operable units. Three have formal Records of Decision covering the Western Groundwater, Perimeter Groundwater, and Boundary areas, using methods such as extraction, bioremediation, soil vapor extraction, carbon adsorption, and institutional controls. Eight additional operable units are still under investigation. A vapor intrusion investigation began in 2017, and remedial design for the Boundary Operable Unit is underway, with action estimated to begin between August and October 2027.
Human exposure is currently under control, but contaminated groundwater migration has not been stabilized. Physical construction is not yet complete, and the site is not ready for its anticipated use. EPA conducts a five-year review to check whether cleanup remains protective. The most recent review occurred in September 2021, and the next is estimated between September and November 2026. Aerojet continues to operate on site, and tenants use portions for office, commercial, and light industrial activities. As of December 2024, five on-site businesses employed 369 people.
Community members can get involved by joining the Aerojet Community Advisory Group. Contact the Community Involvement Coordinator to receive meeting invites and summaries. Site records are available at the Superfund Records Center in San Francisco and the Rancho Cordova Community Library at 9845 Folsom Boulevard in Sacramento. EPA will post the 2026 five-year review report online and send a copy to the information repository by September 30, 2026.
