The Lauer I Sanitary Landfill covers 58 acres near Menomonee Falls, Wisconsin. It accepted municipal and industrial wastes from the mid-1950s through the early 1970s in a sand and gravel pit. Because waste was placed below the groundwater table, leachate migrated into the surrounding aquifer. State inspectors later found leaking pathways between the landfill's leachate collection pond and a ditch draining into the Menomonee River. EPA added the site to the Superfund National Priorities List (NPL) in 1984.
EPA found 23 contaminants of concern across groundwater, soil, and surface water. Groundwater contains metals such as aluminum, antimony, arsenic, barium, cadmium, iron, manganese, mercury, and nickel, along with benzene and chloride. Surface water holds chloroethane, 1,1-dichloroethane, 1,2-dichloroethene, fluoranthene, phenanthrene, pyrene, and toluene. Soil contamination includes polychlorinated biphenyls (aroclors 1254 and 1260), bis(2-ethylhexyl)phthalate, and mixed xylene isomers. Nitrate, nitrite, and sulfate are also present in groundwater.
Cleanup work was led by Waste Management, with the Wisconsin Department of Natural Resources (DNR) overseeing the site and EPA providing additional oversight. A remedial investigation and feasibility study ran from 1990 through 1996, when EPA issued a Record of Decision selecting the final remedy. Between 1996 and 1999, crews installed a multi-layer soil cap, a slurry cut-off wall, leachate extraction and collection systems, and an active landfill gas extraction system. All extracted leachate goes to a municipal wastewater treatment plant. Institutional controls restrict excavation and groundwater use on the property. An asphalt parking lot for garbage vehicles was built as part of the landfill cover.
The site has cleared several key milestones. Human exposure is under control, groundwater migration is stabilized, and the site reached "sitewide ready for anticipated use" status in August 2010. One business currently operates on the property, employing 50 people. Five-year reviews have been completed in 2002, 2007, 2012, 2017, and September 2022. The most recent review confirmed that response actions protect human health and the environment in the short term. Long-term protectiveness depends on maintaining remedy components and meeting all groundwater cleanup goals. The next five-year review is expected between September and November 2027. The site has not yet been deleted from the NPL.
Community members with questions can contact EPA's Remedial Project Manager or Community Involvement Coordinator. State-level questions can go to the Wisconsin DNR.
