The Stanley Kessler Company ran a degreasing and welding wire repackaging operation on a 3-acre property in King of Prussia, Montgomery County, Pennsylvania. Solvent degreasers spilled into floor drains connected to an unlined cesspool, allowing chemicals to reach the soil and groundwater below. In 1979, organic compounds including trichloroethylene (TCE) and 1,1,1-trichloroethane (TCA) turned up in the Upper Merion Reservoir, a drinking water source for the Philadelphia Suburban Water Company about half a mile away. EPA added the site to the National Priorities List (NPL) in September 1983.
Twelve volatile organic compounds (VOCs) have been identified as contaminants of concern, all found in groundwater. They include TCE, TCA, benzene, chlorobenzene, tetrachloroethene, and several other chlorinated solvents. Early cleanup steps in 1981 removed liquid wastes and 60 to 80 cubic yards of contaminated soil from the cesspool and septic tank. A groundwater recovery and treatment system ran from 1984 to 1990. After a remedial investigation completed in 1992, EPA selected a final remedy in September 1994. That remedy uses vertical extraction wells, activated carbon to treat the pumped groundwater, deed restrictions to block new wells, and ongoing monitoring. Construction of the system was finished in November 1998, with an additional extraction well added in February 2003.
Groundwater treatment is ongoing under EPA oversight, with semi-annual monitoring carried out by the responsible parties. Drinking water supplied from the Upper Merion Reservoir is treated before it reaches customers, so people are not exposed to site-related contamination through their taps. Deed restrictions prevent anyone from drilling new groundwater wells at the property. Zoning restrictions also block residential uses that would be inconsistent with the cleanup level achieved. The site reached "sitewide ready for anticipated reuse" status in September 2014, and two industrial tenants currently operate there. The most recent five-year review was completed in July 2024. The site has not yet been deleted from the NPL.
Community members with questions can contact EPA's Community Involvement Coordinator or Remedial Project Manager directly. Administrative records for the site, including 77 remedial documents, can be viewed at the Upper Merion Township Library at 175 West Valley Forge Road in King of Prussia or at EPA Region 3 in Philadelphia. To schedule an appointment to review the administrative record, call EPA at 215-814-2396.
