Alameda Naval Air Station is a closed Navy installation covering 2,806 acres on Alameda Island in California. It was added to the EPA's National Priorities List (NPL) in July 1999. The site generated industrial wastes over decades of military use, and before 1974, untreated liquid wastewaters flowed directly into Seaplane Lagoon and Oakland Inner Harbor. That discharge left behind contaminated sediment and underground plumes of dense non-aqueous phase liquid (DNAPL), a type of hard-to-remove chemical pool that can persist in soil and rock for years.
More than 150 chemical substances have been identified as contaminants of concern across groundwater, soil, surface water, sediment, and solid waste. These include chlorinated solvents such as trichloroethene and tetrachloroethene, metals such as lead, arsenic, chromium, and cadmium, polychlorinated biphenyls (PCBs), pesticides including DDT and dieldrin, polyaromatic hydrocarbons, benzene, and radioactive substances such as radium-226 and uranium-238. EPA determined these contaminants pose an unacceptable risk to human health and the environment. The contamination also threatens aquatic life in San Francisco Bay and terrestrial animals in the area.
The Navy leads cleanup with EPA oversight. The California Department of Toxic Substances Control and the San Francisco Bay Regional Water Quality Control Board also assist. The site is divided into 22 operable units, each targeting a specific geographic area or contamination problem. Cleanup methods include excavation, bioremediation, chemical oxidation, monitored natural attenuation, and institutional controls such as zoning restrictions that prevent residential development. Several operable units have completed remedial action and moved into operation and maintenance phases. Others are still in active remediation or remedial design. A final remedy was selected in September 2023 for at least one unit, and work at some locations is estimated to continue through 2027 and 2028. The most recent five-year review was completed in September 2021.
Current assessments show human exposure is under control, meaning no unacceptable pathways for people to contact contaminants currently exist. Groundwater migration is also stabilized. However, physical construction of the cleanup is not complete, and the site has not been deleted from the NPL. Remediation of the DNAPL plumes remains a long-term challenge.
Community members can stay involved through the Alameda Point Restoration Advisory Board, which has met every other month since 1993 and includes Navy, community, regulatory agency, and City of Alameda representatives. The board meets on the second Thursday of January, March, May, July, September, and November. The EPA's Community Involvement Coordinator and Remedial Project Manager are available for questions. Copies of site documents are available through the Navy, the Public Information Repository, or either EPA contact.
