The King of Prussia site sits in Winslow Township, New Jersey, and has been on the EPA's National Priorities List (NPL) since 1983. It operated as an industrial waste treatment facility from 1970 to 1975, processing roughly 15 million gallons of wastewater through six lagoons. The operator went bankrupt, and the site was abandoned in 1975. It was fenced in 1988 to stop further dumping.
Contamination is widespread across soil, groundwater, surface water, sediment, debris, and solid waste. Heavy metals found at the site include arsenic, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, and zinc. Chlorinated compounds such as trichloroethene and tetrachloroethene have been detected, along with pesticides like chlordane, DDT, and dieldrin. Volatile organic compounds including benzene, toluene, ethylbenzene, and xylene are also present, as are phenol, pentachlorophenol, naphthalene, and phthalates.
EPA organized cleanup into four operable units (OUs) covering soils, drum removal, groundwater, and sitewide activities. Work started with removal of buried containers, drums, and tankers in 1989 and 1990. From 1993 to 1994, a soil washing system treated over 19,000 tons of metal-contaminated soil. A groundwater pump-and-treat system began operating in March 1995 and ran continuously until May 2019, when it was shut down after groundwater quality improved. The responsible party continues to monitor groundwater and will restart treatment if contamination rises to unacceptable levels. Construction of all cleanup work was completed in September 1995, and a "no further action" decision was issued for the drum disposal area that same year. Operable Unit 3, covering groundwater, has not yet received a formal decision document.
Human exposure is under control, and contaminated groundwater migration is stabilized with no unacceptable discharge to surface water. The site reached sitewide ready for anticipated reuse status in March 2013, meaning all cleanup goals for current and future land uses have been met and required land-use controls are in place. The most recent five-year review, the sixth for this site, was completed in June 2025. Multiple prior reviews since 2000 have confirmed that cleanup actions remain protective of human health and the environment. The site has not yet been deleted from the NPL.
Community members with questions can contact the EPA's Community Involvement Coordinator. Technical questions about remediation can be directed to the Remedial Project Manager. Site records are available for public review at the Camden County Library in Voorhees, New Jersey, or at the EPA's Superfund Records Center at 290 Broadway in New York City.
