Tinker Air Force Base sits in Oklahoma County, Oklahoma, and covers about 5,000 acres with roughly 500 buildings. The site landed on the National Priorities List (NPL) in 1987. Industrial operations and waste disposal at Building 3001, a large aircraft rebuilding facility, released solvents and other hazardous chemicals into soil and groundwater from 1942 until 1979. The Air Force owns and operates the facility and is responsible for cleanup. EPA serves as the lead regulatory agency under CERCLA, the federal Superfund law.
EPA has identified 34 contaminants of concern across the site. At Building 3001, groundwater holds solvents such as trichloroethene, tetrachloroethene, and vinyl chloride, plus heavy metals including chromium, lead, and nickel. Soil at that location contains compounds like benzene, toluene, and xylene. Soil gas holds chlorinated solvents as well. At Soldier Creek, sediments and surface water contain cadmium, chromium, lead, chloroform, and additional chlorinated solvents.
The site is divided into four operable units (OUs). At Building 3001 (OU1), a pump-and-treat groundwater system ran from 1990 to 2006. A 2014 Record of Decision Amendment added soil vapor extraction and chemical oxidation injections as in-place treatments. Three horizontal extraction wells came online in November 2015, and chemical oxidation injections were performed at two spots in early 2018. Some planned actions under that amendment are still incomplete. For Soldier Creek sediment and surface water (OU2), monitoring ended after risk evaluations through 2006 found no risk to human health or the environment. Soldier Creek groundwater (OU3) received a no-further-action decision in 2008. The Industrial Waste Treatment Plant groundwater (OU4) is still under investigation, with a Record of Decision estimated for early 2028.
EPA assessments show human exposure to contaminants is currently under control, and contaminated groundwater is stabilized with no unacceptable discharge to surface water. Physical construction is not yet complete. The most recent five-year review, finished August 12, 2022, found cleanup actions are protective in the short term but noted that more information is needed to confirm long-term protectiveness. A focused remedial investigation is underway to gather that information. Overall site construction is estimated to wrap up between December 2027 and February 2028, with the next five-year review estimated for fall 2027.
Community members with questions can contact the EPA Community Involvement Coordinator or the Remedial Project Manager. The Air Force maintains the Administrative Record, which can also be accessed through the site's Public Information Repository.
