The Westinghouse Electric Sharon Plant operated from 1922 to 1985 on a 58-acre property in Mercer County, Pennsylvania, making electrical transformers. The facility used polychlorinated biphenyls (PCBs) and trichlorobenzene between 1936 and 1976. Decades of leaks and spills spread contamination into site soils, groundwater, sediments in the nearby Shenango River, and the river's floodplain soils. EPA added the site to the Superfund National Priorities List in August 1990.
The site has 20 identified contaminants of concern. These include PCBs in multiple forms, chlorinated compounds like trichloroethene and tetrachloroethene, benzene, vinyl chloride, metals including arsenic, cadmium, chromium, and mercury, a highly toxic dioxin compound called 2,3,7,8-tetrachlorodibenzo-p-dioxin, and the phthalate bis(2-ethylhexyl)phthalate. All 20 contaminants are tracked in groundwater and sediments under Operable Unit 2 of the site.
Cleanup is divided into two operable units. For soils, about 35,400 tons of PCB-contaminated material were excavated and removed from the site. Soil construction was completed and confirmed protective of human health and the environment, though a 2020 plan modification addressed contamination above revised cleanup standards. For groundwater and sediments, work began in 2004 and was completed in 2006, removing PCB-contaminated sediments and riparian soils from the Shenango River. A second groundwater remedial action phase ran from April to May 2024. However, recent sampling found sediments near the site had been re-contaminated from PCB releases through a storm sewer, and investigations to stop that source were underway. Institutional controls remain in place to restrict groundwater use, prevent residential development, and limit fish consumption.
The 2021 Five-Year Review found the remedy continues to protect human health and the environment in the short term. A Do Not Eat Fish advisory covers all fish species in the Shenango River, first issued by Pennsylvania in 2016 and 2017 after high PCB levels were found in fish tissue. A fish consumption advisory from the Pennsylvania Department of Environmental Protection has also been in effect since 2017. The site has not yet been deleted from the National Priorities List, though nine businesses now operate on the property, employing 409 people and generating about $87.7 million in annual sales. The next five-year review is scheduled for 2026.
Community members can access fact sheets going back to 1996, a community involvement plan from 1999, public meeting slides, and information on vapor intrusion sampling and fish advisories. Physical records are held at the Community Library of the Shenango Valley in Sharon, reachable at (724) 981-4360, and at EPA Region 3 in Philadelphia by appointment at (215) 814-2396. To ask questions or share input for the upcoming review, contact the EPA's Community Involvement Coordinator or Remedial Project Manager.
