Walsh Landfill

Overview

Walsh Landfill operated as an unpermitted dump in Honeybrook Township, Chester County, Pennsylvania from 1963 to the mid-1970s, accepting industrial, hazardous, and municipal waste. EPA added it to the Superfund National Priorities List (NPL) in September 1984. The site covers about 7 acres and spans portions of Chester and Lancaster counties.

The landfill contaminated soil, sediment, surface water, and groundwater. EPA identified 27 contaminants of concern. Heavy metals include arsenic, lead, cadmium, mercury, nickel, manganese, barium, and thallium. Volatile organic compounds (VOCs) include benzene, trichloroethene, tetrachloroethene, chloroform, ethylbenzene, xylene, and 1,1-dichloroethane. The site also contains 1,4-dichlorobenzene and polycyclic aromatic hydrocarbons (PAHs). Residential well water was among the affected resources, prompting Pennsylvania to provide bottled water to 44 homes starting in 1989. EPA determined that arsenic found in groundwater is not related to the site.

Cleanup has addressed the site in stages. Forty-five homes were connected to a municipal water line by 1998, and that water line extension was completed in 2010. A 1990 Record of Decision (ROD) called for capping the landfill, but a 2003 ROD Amendment changed the approach. Instead of a conventional cap, potentially responsible parties (PRPs) installed an evapotranspiration (ET) cover system, completed in 2006. The ET cover uses soil planted with 4,100 deep-rooting hybrid poplar trees and native shallow-rooting plants. The trees absorb rainwater and reduce water from seeping into the landfill and reaching groundwater. A separate 2006 ROD selected monitoring and institutional controls for groundwater. Deed notices recorded in 2006 restrict future land uses to protect the remedy and prevent groundwater exposure. The poplar trees now reach 16 to 20 feet tall and support ecological reuse at the site.

All physical construction is complete. The site achieved Construction Complete status and is designated Sitewide Ready for Anticipated Use. All exposure pathways that could cause unacceptable health risks are under control, and contaminated groundwater migration is stabilized with no unacceptable discharge to surface water. Annual groundwater monitoring continues. EPA completed its sixth Five-Year Review in April 2026, confirming the remedy remains protective of human health and the environment. The next five-year review is scheduled for 2031.

Community members can review site records at the Honey Brook Community Library, 687 Compass Road, Honey Brook, Pennsylvania. Records are also available at EPA's Region 3 office in Philadelphia, by appointment. For questions, contact the EPA site team using the information below.