Master Disposal Service Landfill operated from 1967 to 1982 in Brookfield, Wisconsin, accepting about 1.4 million cubic yards of waste, including industrial solvents, paints, adhesives, oils, and foundry waste. The site sits on the marshy floodplain of the Fox River headwaters. EPA placed it on the National Priorities List in September 1984 after assessing it in May 1983.
EPA identified 17 contaminants of concern. These include metals such as arsenic, cadmium, chromium, copper, and lead, and volatile organic chemicals like benzene, toluene, trichloroethene, xylene, dichloromethane, and 1,1-dichloroethene. Groundwater is the most frequently affected medium, though contaminants also appear in surface water and solid waste.
Cleanup was organized into two operable units. The first addressed the landfill itself and groundwater treatment. Workers installed an engineered cap with a gas control system and ran an extraction system using 11 wells. Water was treated in a settling pond where aeration and bacteria broke down organic compounds before the water moved through wetlands into the Fox River. Physical construction of this work finished in June 1997. The second operable unit focuses on groundwater restoration. A 2007 EPA decision established a plan relying on monitored natural attenuation to address remaining benzene, with the pump-and-treat system ready to restart if contamination threatens to spread off-site. In 2016, EPA and the Wisconsin Department of Natural Resources replaced deed restrictions with state and local governmental controls to manage future land and groundwater uses.
Today, groundwater contamination is the only remaining potential risk, but there are no current exposures to contaminated groundwater. EPA has determined that human exposure is under control and that groundwater migration is stabilized. The site was declared ready for anticipated reuse in August 2017. EPA completed a five-year review in April 2025 to confirm the cleanup remains protective. The site has not yet been deleted from the National Priorities List.
Community members can review site records at the Brookfield Public Library at 1900 N. Calhoun Road in Brookfield. For general questions, contact the EPA Community Involvement Coordinator. For technical questions, contact the Remedial Project Manager. Questions can also be directed to the Wisconsin Department of Natural Resources.
