The N.W. Mauthe Co., Inc. site sits in Appleton, Wisconsin, where an electroplating facility operated from 1978 to 1987. The facility plated zinc, cadmium, copper, and possibly silver. Those operations left soil and groundwater contaminated with hazardous chemicals. EPA added the site to the National Priorities List (NPL) in 1989. The NPL is the federal government's roster of the most serious known or threatened releases of hazardous substances.
Contaminants of concern span several chemical groups. Chlorinated solvents include trichloroethene, 1,1,1-trichloroethane, and related compounds. Organic chemicals such as benzene, toluene, and xylene were also detected. Metals and metalloids found at the site include cadmium, chromium, lead, mercury, and zinc, among others. Cyanide was identified across multiple types of environmental media, including soil, groundwater, and surface water.
EPA and the Wisconsin Department of Natural Resources (WDNR) finalized a cleanup plan in 1994. Construction of the remedy wrapped up by 1998 and included building demolition, removal of contaminated soil, installation of a groundwater collection and treatment system, capping the site with clay and topsoil, and deed restrictions to limit future land use. The WDNR now handles ongoing operation and maintenance. The 2021 Five-Year Review found that cleanup actions remain protective of human health and the environment. Human exposure and groundwater migration are both listed as under control. The site achieved "sitewide ready for anticipated reuse" status in September 2019, meaning all cleanup goals for current and future land uses have been met and required land-use controls are in place.
One active issue remains. Vapor intrusion sampling conducted from 2023 to 2024 found a complete vapor intrusion pathway at an unoccupied building on the site property. Vapor intrusion happens when chemicals in the ground move upward into the air inside a building. EPA and WDNR are working to determine the best way to reduce vapor exposure inside that building. EPA is also conducting a sixth five-year review, expected to be completed between May and July 2026. The site has not yet been deleted from the NPL.
Community members who want to share observations about current site conditions or raise concerns can do so through the five-year review process. Superfund law requires these regular checkups at sites where cleanup is complete and waste remains on-site. For direct questions, residents can contact the EPA's Community Involvement Coordinator or the Remedial Project Manager.
