Washington County, Minnesota – November 2025
The U.S. Environmental Protection Agency is currently completing an investigation of contaminants at the Baytown Township Ground Water Plume Superfund Site. The purpose of the investigation is to collect additional groundwater and soil data to confirm the known source area. This work will inform whether alternative cleanup methods can address the continuing migration of contamination from the source area, and speed up the cleanup process. Minnesota Pollution Control Agency, or MPCA, continues to monitor private drinking water wells and install granulated activated carbon filters for eligible wells as needed.
Site Background
The Baytown Township site is in central Washington County, Minnesota. It includes parts of Baytown Township, West Lakeland Township, and parts of the cities of Bayport and Lake Elmo. The site consists of a groundwater plume, contaminated predominantly with trichloroethene, or TCE. The contaminated plume covers about seven square miles. Treatment of private and public drinking water, groundwater monitoring, and a source area investigation are ongoing.
The primary source of site contamination is a former metalworking facility in Lake Elmo that operated from 1940 to 1968. The Minnesota Department of Health, or MDH, first detected TCE in private wells in 1987. MDH created a Special Well and Boring Construction Area to protect residents; to inform well owners and drillers about the potential for contaminated groundwater in the area; and to prevent further degradation of the aquifer by requiring proper construction of new wells. There are over 900 residential water supply wells in this area that provide drinking water to the individual residents.
The site was listed on the state’s Permanent List of Priorities in 1988 and added to the National Priorities List in 1994. The MPCA assumed responsibility for regulatory oversight of the site in 1995. In 2000, MPCA and EPA selected a remedy for the groundwater plume and private wells. This remedy included plume monitoring; the installation and maintenance of activated carbon treatment units for private wells; and maintenance of the Special Well and Boring Construction Area.
From 2007 to 2013, MPCA and EPA amended the remedy to add drinking water treatment for the city of Bayport Municipal Well #2 and #3; treatment for the source area of the contamination; and a groundwater containment system to delay the spread of contamination from the source area. The Record of Decision Amendment separated the site into three Operable Units (OU) including OU1 – private wells and groundwater plume, OU2 – city of Bayport municipal wells and OU3 – the source area. MPCA was the lead agency for all three OUs until September 2023, at which time EPA became the lead agency for activities associated with OU3.
Other Contaminants
Some per- and polyfluoroalkyl substances, or PFAS chemicals have been detected at the site. PFAS are chemicals that are stable and persistent in the environment. Many PFAS may pose a public health or environmental risks, even at low concentrations. As of April 2024, PFAS maximum contaminant levels are enforceable under the federal safe drinking water act for several PFAS in drinking water. PFAS investigations at the Site are ongoing.
Reference: EPA to Investigate Groundwater Contamination
