Dover Air Force Base sits on roughly 4,000 acres in Kent County, Delaware, and has operated since December 1941. Past military activities contaminated soil and groundwater across the installation. EPA added the site to the Superfund National Priorities List in March 1989. The Air Force, EPA, and Delaware's Department of Natural Resources and Environmental Control then signed a Federal Facilities Agreement to guide the work.
Contaminants found at the site include chlorinated solvents such as trichloroethene and tetrachloroethene, fuel-related compounds like benzene and toluene, heavy metals including arsenic, lead, and cadmium, pesticides such as dieldrin and DDT variants, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). In 2014, per- and polyfluoroalkyl substances (PFAS), specifically PFOA and PFOS, were found in on-base groundwater and later in off-base private wells. PFAS were likely introduced through aqueous film-forming foam used in firefighting. Filtration systems have been installed on affected private wells. Twelve groundwater plumes have been identified both on and off the base, and contamination has also been detected in soil, drainage ditches, surface water, and sediments.
The site is divided into 25 operable units. Remedies range from soil excavation and capping to monitored natural attenuation and in-situ anaerobic bioremediation, which uses microbes to break down contaminants in place. A 2023 amendment to the cleanup plan updated the approach for the Fire Training Area 3 groundwater unit. A new remedial action for that unit is scheduled to begin in April 2025. One operable unit addressing PFAS contamination has no cleanup decision yet. Land use controls restrict residential construction, daycares, schools, and groundwater use in contaminated areas. Construction of cleanup measures across most units is complete, but human exposure is not yet under control and groundwater migration is not stabilized.
The sources note two different dates for the most recent five-year review completion: the cleanup section states it was conducted in 2018, while the cleanup progress section states it was completed on September 28, 2023. The community section adds that the Air Force submitted its Sixth Five-Year Review on June 4, 2025, and EPA issued a determination on July 30, 2025. Community members can attend events like the Information Poster Session held June 5, 2025, which covered PFAS impacts and regulatory changes. For questions or to learn about future engagement opportunities, contact Dover AFB Public Affairs at 436AW.PA@us.af.mil or 302-677-3372. Prior coordination is required to visit the base.
