Waste Management of Wisconsin operated a 20-acre sanitary landfill in Brookfield, Wisconsin from 1969 to 1981. The site was added to the federal National Priorities List (NPL) in August 1990, placing it among the country's most serious hazardous waste sites. Groundwater monitoring in 1985 detected cyanide contamination at the site.
Physical cleanup construction wrapped up in 1991. Workers placed a new clay cap over the landfill, graded and vegetated it to prevent erosion, and built drainage ditches to direct runoff away from the site. A flare system extracts and destroys landfill gas, and gas probes track methane levels and pressure. The remedy is designed to stop direct contact with contaminated materials, reduce water moving through the waste, and safely vent landfill gases.
The Wisconsin Department of Natural Resources (DNR) oversees the site under its Closure Long-Term Care Plan. Ongoing operation, maintenance, and monitoring activities continue under that plan. The U.S. Environmental Protection Agency (EPA) has determined that human exposure is currently under control, with no unacceptable exposure pathways. Contaminated groundwater migration is also stabilized, and there is no unacceptable discharge to surface water. Monitoring continues to confirm that affected groundwater stays within the original contamination area.
The site is not yet ready for all anticipated uses. Not all cleanup goals for current and future land uses have been met, and required land-use restrictions have not all been put in place. Redevelopment may still occur on portions of the site through EPA's Superfund Redevelopment Program, which works with communities to return sites to productive use.
Community members with questions can contact EPA's Community Involvement Coordinator or Remedial Project Manager.
