Walker Machine Products, Inc. operated in Collierville, Tennessee from the mid-1960s until 2002, manufacturing precision metal parts using cutting oils and chlorinated solvents. Spills and leaks contaminated soil and groundwater beneath the site. EPA added the site to the National Priorities List in May 2014.
EPA has identified 14 contaminants of concern, including trichloroethene (TCE) and tetrachloroethene (PCE) as the most widespread. These and related chlorinated compounds were found in groundwater, soil, soil gas, and indoor air. Groundwater contamination sits roughly 60 to 80 feet below the surface. A vapor control system was installed in the main plant building to address vapor intrusion risks from chemicals moving through the soil beneath the building slab.
EPA selected a cleanup plan in September 2018 targeting volatile organic compounds (VOCs) in three phases. The first phase uses thermally enhanced soil vapor extraction, air sparging, and excavation of roughly 900 cubic yards of soil. The second phase applies biogeochemical reductive dehalogenation with injection and recovery wells. The third phase uses enhanced in-situ bioremediation for the dilute contaminant plume. Soil excavation began in late March 2024, with vapor extraction and air sparging equipment installed from May through August 2024. Those systems are scheduled to run through September 2026. Whether the second and third phases are needed depends on how well the first phase performs. Cleanup funding has come partly through the Bipartisan Infrastructure Law. Full construction completion is estimated for late 2027 or early 2028.
According to EPA assessments, human exposure is currently under control. There are no unacceptable human exposure pathways at this time, and groundwater contamination is stabilized in its original area. Physical construction of the cleanup is not yet complete, and the site is not yet ready for its anticipated future use. EPA will continue monitoring to confirm the contamination stays contained.
Community members can stay informed through public notices, public meetings, and updates that EPA issues throughout the cleanup process. Site records are available for public review at the Lucius E. and Elsie C., Jr. Library in Collierville. Work opportunities with EPA or its contractors are posted at sam.gov/content/opportunities. Two EPA staff members handle community and technical questions for this site.
