Norton Air Force Base sits in San Bernardino, California, and operated as a major jet engine and aircraft repair facility starting in 1942. It was added to the National Priorities List on July 22, 1987. Past operations left behind a wide range of contaminants in soil and groundwater across the site.
Groundwater in the Central Base Area contains solvents including trichloroethene, tetrachloroethene, benzene, vinyl chloride, 1,1,1-trichloroethane, 1,2-dichloroethane, and 1,2-dichloroethene. Air in that same area contains vinyl chloride. Soil across the broader base contains benzene, polychlorinated biphenyls (PCBs), metals such as arsenic, lead, cadmium, chromium, mercury, nickel, and zinc, pesticides including chlordane, and other substances like cyanide and radium-226. Health risks come primarily from people ingesting or touching contaminated soil.
The Air Force is the lead agency for cleanup. Remedies include groundwater extraction with air stripping treatment, soil vapor extraction, institutional controls that restrict residential use in certain areas, and removal actions. In 2019, the Air Force finished removing lead-contaminated soils from a former Small Arms Range. Physical construction of all remedies was completed in 2006, and the groundwater remedy has achieved its cleanup objectives. Ongoing work includes groundwater monitoring, landfill gas monitoring, inspections, and cap maintenance. The site is divided into two operable units. The Central Base Area (Operable Unit 01) has a 1993 Record of Decision. The Basewide area (Operable Unit 02) has decisions from 1997 and 2005, with a 2005 amendment adding excavation and offsite disposal.
The EPA has conducted multiple five-year reviews. The most recent was completed on September 30, 2025. The EPA deferred its protectiveness statement from an earlier review pending more information about whether per- and polyfluoroalkyl substances (PFAS) in soils and groundwater pose current risks to people or the environment. Human exposure status is currently uncertain because response efforts have not yet produced enough reliable data to confirm whether unacceptable exposure pathways exist. An Explanation of Significant Differences for the Basewide operable unit is estimated to be completed between December 2025 and February 2026. The site has not yet been deleted from the National Priorities List. Note that one source states the site met EPA Sitewide Ready for Anticipated Use criteria in 2007, while another states the site has not yet achieved that status sitewide. Much of the former base now operates as an airport with warehouse and distribution centers, with tenants including Stater Brothers, Mattel, PEP Boys, and Amazon.
Community members with questions can contact the EPA Remedial Project Manager or the Community Involvement Coordinator. The Administrative Record is available on the Air Force website at https://ar.afcec-cloud.af.mil/ by selecting BRAC and then Norton AFB.
