Sauk County ran a municipal landfill on a 320-acre parcel in Excelsior, Wisconsin from 1973 to 1983, disposing of municipal, commercial, and industrial waste across about 14 acres. The landfill contaminated groundwater with volatile organic compounds and metals. EPA added the site to the Superfund National Priorities List (NPL) in 1989, and the agency selected a final cleanup plan in 1995.
The contaminants of concern identified at the site are arsenic, beryllium, lead, manganese, and polycyclic aromatic hydrocarbons (PAHs). These substances were found in solid waste and were determined to pose unacceptable risks to human health or the environment. The greatest potential health threat was drinking contaminated groundwater or inhaling vapors from it.
The cleanup included installing a multi-layered cap over the landfill, a gas extraction system, and groundwater monitoring wells. The gas extraction system uses a flare to destroy landfill gas. In a productive reuse of that gas, the site later installed microturbines to convert methane into electricity, eventually expanding to 24 microturbines that generate enough power for over 300 homes. The Wisconsin Department of Natural Resources (DNR) oversees all operation and maintenance work. Monitoring wells are sampled twice a year.
The site currently poses no health threat. Contaminant concentrations have been decreasing and drop off sharply a short distance from the landfill. EPA has confirmed that human exposure is under control and that contaminated groundwater has stabilized within its original area. EPA completed its fifth five-year review of the site, finding that the cleanup continues to protect people and the environment. The next scheduled review is set for 2025. The site has not yet been deleted from the NPL.
Community members with questions can contact the EPA's Community Involvement Coordinator or Remedial Project Manager. State-level questions can be directed to the Wisconsin DNR.
