From 1943 to 1982, an industrial complex in LaSalle, Illinois made capacitors and left behind polychlorinated biphenyls (PCBs) and chlorinated solvents in soil, groundwater, sediment, and buildings. The site was added to the National Priorities List (NPL), a federal registry of the country's most contaminated sites, in September 1983 and remains on that list today.
Cleanup happened in three phases. Phase I removed more than 23,000 cubic yards of PCB-contaminated soil from residential yards, roads, fields, and nearby properties. Twenty-six homes were temporarily evacuated, and over 100 more had partial yard or curb work done. Phase II, from 1990 to 1994, demolished the industrial complex, recycled decontaminated steel, and thermally destroyed PCB-contaminated soil, building debris, and stream sediments. Phase III targeted groundwater, with a collection and treatment system running since spring 1995, a soil vapor extraction system added in 2002, and plants used in select spots to pull volatile organic compounds from clay soils.
Specific contaminants in soil and groundwater include 1,1,1-trichloroethane, 1,1-dichloroethane, 1,1-dichloroethene, vinyl chloride, chloroform, tetrachloroethene, and trichloroethene. PCBs, including the products Aroclor 1248 and Aroclor 1254, were found in soil, groundwater, sediment, and buildings both on and off the main site. Physical construction of the cleanup is complete across the entire site, but monitoring continues. The status of human exposure control and contaminated groundwater migration control cannot yet be determined due to insufficient data.
Illinois EPA now leads operation and maintenance. The sixth five-year review, completed in August 2024, found that protectiveness of the site could not yet be fully determined. EPA plans soil gas sampling at nearby properties to check for vapor intrusion, a process where contaminated air from soil can seep into buildings. Depending on those results, indoor air testing may follow. EPA expects to finish that sampling and issue an updated protectiveness finding by fall 2027. A Record of Decision amendment and remedial design for the on-site area are estimated between September and November 2028. Flooding in 2011 damaged the groundwater treatment building, and Illinois EPA is re-evaluating that treatment approach. Deed notices restrict how certain properties can be used, and compliance with local ordinances is required until groundwater cleanup is complete.
Community members with questions can contact the EPA's Community Involvement Coordinator or Remedial Project Manager.
