Henderson Road

Overview

The Henderson Road site covers 7 acres in Upper Merion Township, Montgomery County, Pennsylvania. O'Hara Sanitation Company used the property starting in 1975 for waste storage, recycling, and vehicle maintenance. Workers disposed of industrial liquid wastes in a former water supply well during the 1970s, and an unpermitted landfill received construction debris, commercial waste, and drums. EPA added the site to the National Priorities List in 1984, which flags it for formal cleanup attention.

Soil and groundwater are contaminated with volatile organic compounds including benzene, trichloroethene, tetrachloroethene, vinyl chloride, chloroform, and xylenes, along with metals such as cadmium, lead, and chromium. The landfill area also contains pesticides like aldrin and DDT, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. The primary health risk is drinking contaminated groundwater. Over 100 chemical substances have been identified as contaminants of concern across the two main areas: the injection well zone and the landfill.

EPA divided the site into six operable units to target specific problems. Physical construction was completed in October 1992, and a landfill cap is in place to prevent erosion and limit leachate. In February 2023, EPA finalized a Record of Decision Amendment for the injection well area. The new approach replaces groundwater extraction and treatment with in-situ bioremediation, a method that breaks down contamination underground using biological processes. Current work includes running a vapor extraction system, removing light non-aqueous phase liquid, monitoring vapor intrusion in the on-site building, and sampling groundwater every quarter.

EPA's 2023 five-year review found the site is currently protective of human health and the environment. Human exposure is under control across the entire site, and groundwater contamination has stayed within the original area. The site achieved ready-for-anticipated-reuse status in 2013, and Republic Services currently operates offices and a maintenance garage there. Full aquifer restoration to meet long-term cleanup goals is still ongoing, and the next five-year review is scheduled for 2028. The site has not yet been deleted from the National Priorities List.

Community members can get involved through EPA's Superfund community involvement process, which supports open dialogue about cleanup progress and health protections. Administrative records are available online or in person at Upper Merion Library at 175 West Valley Forge Road in King of Prussia, or at the U.S. EPA Region 3 Public Reading Room at 1600 John F. Kennedy Boulevard in Philadelphia. Appointments at the Philadelphia location can be scheduled by calling (215) 814-2396.