The DuPage County Landfill/Blackwell Forest Preserve is a former 40-acre landfill that operated from 1965 to 1973 in Warrenville, Illinois. It sits inside a 1,200-acre forest preserve used daily by the public for recreation. DuPage County's landfill operations created a 150-foot hill known as Mt. Hoy. EPA added the site to the National Priorities List in February 1990 after finding groundwater contamination, and deleted it from that list on September 8, 2020, marking the formal end of the high-priority cleanup process.
EPA identified more than 130 contaminants of concern across groundwater, surface water, and soil. These include volatile organic chemicals such as benzene, trichloroethene, and vinyl chloride, as well as pesticides like dieldrin and DDT compounds, polycyclic aromatic hydrocarbons, polychlorinated biphenyls (PCBs), and metals including lead, arsenic, and copper. The migration of contaminated groundwater has been stabilized, and there are no unacceptable discharges to surface water.
EPA selected the final remedy in September 1998. Cleanup actions include an engineered landfill cap, a leachate extraction and treatment system, landfill gas venting through a single stack installed in 2001, monitored natural attenuation of groundwater, and institutional controls such as zoning restrictions that prevent residential development and limit incompatible land uses. Construction of all cleanup components was completed in September 1998. Long-term monitoring and maintenance of the leachate treatment system will continue for at least 20 years.
EPA has conducted regular five-year reviews to confirm the remedy continues to protect public health and the environment. The most recent review, completed July 14, 2023, found that response actions match the selected remedy and remain protective. Human exposure is currently under control across the entire site, with no unacceptable exposure pathways identified. The site achieved "sitewide ready for anticipated reuse" status in November 2008. Today it operates as a recreation area featuring restored native prairie, trails, picnic areas, a snow tubing run on Mt. Hoy, two fishing lakes, and an archery range. The next five-year review is estimated between July and September 2028.
Community members with questions can contact EPA's Community Involvement Coordinator or Remedial Project Manager directly. Their contact details appear in the contacts section below. EPA, Illinois EPA, and responsible parties cooperated throughout the cleanup while keeping the forest preserve open to the public.
