The City Disposal Corp. Landfill covers 38 acres in a rural area northeast of Oregon, Wisconsin, in Dane County. It accepted household, industrial, and construction waste, including paint manufacturing solvents and oily residues, from the mid-1960s until 1977. About 700,000 cubic yards of waste were disposed there. The site was added to the EPA's National Priorities List in September 1984 and has been in active cleanup ever since. It reached sitewide ready for anticipated reuse status in June 2015 but has not yet been deleted from the National Priorities List.
Tetrahydrofuran is the primary contaminant of concern. EPA has identified 43 contaminants total, found in solid waste, groundwater, and soil. These include heavy metals such as arsenic, cadmium, chromium, lead, and mercury, along with organic chemicals like toluene, ethylbenzene, various phthalates, acetone, naphthalene, phenol, and cyanide. Volatile organic compounds, which are chemicals that can evaporate into the air, remain present in groundwater and soil. People could be exposed by drinking contaminated groundwater, accidentally swallowing contaminated soil, breathing contaminated dust or air, or touching contaminated groundwater and soils directly.
Cleanup construction began in March 1995 and was completed in June 2000. Actions included placing an engineered cap over the landfill, installing a landfill gas collection system, extracting and treating contaminated groundwater through vertical wells, and using soil vapor extraction to remove vapors on-site. A fixed-film bioreactor system was installed in 2000 to treat water through a wetland before it discharges to Badfish Creek. Institutional controls, including zoning restrictions, are in place to prevent land uses that are incompatible with the cleanup level achieved. Waste Management of Wisconsin operates and maintains these systems under EPA and Wisconsin Department of Natural Resources oversight.
EPA has determined that human exposure is currently under control and that there are no unacceptable human exposure pathways across the entire site. Groundwater migration is also under control, with no unacceptable discharge to surface water. The EPA continues groundwater monitoring to ensure contamination stays within its original area. The most recent five-year review was completed in September 2021, and the sixth five-year review is underway, expected to be completed by spring 2026, with the next scheduled review estimated between September and November 2026.
Community members can review site records at Dunn Town Hall, located at 4156 County Trunk Highway B in McFarland, Wisconsin. Over 160 documents are available through EPA's Superfund database. The five-year review process gives the public a chance to share observations and concerns about site conditions directly with the EPA. For questions, residents can contact the Remedial Project Manager or the Community Involvement Coordinator.
