St. Louis Park | Highway 100 and County Road 3 area groundwater contamination

Groundwater contamination has been identified in two St. Louis Park municipal wells and three Edina municipal wells. The large underground plume has contaminated drinking water at levels exceeding standards. Both cities have worked with the MPCA and MDH to design treatment systems that remove contaminants from drinking water before it is distributed to the public.

Health and environmental concerns

The contamination has produced chemical vapors in the soil, and these vapors can make their way into houses and buildings. The contamination also affects deep groundwater in a plume that underlies a large portion of both cities.

Next steps and timeline

Although contamination is present, all known immediate risks have been addressed. Vapor mitigation systems were installed in the shallow groundwater area. Both cities treat drinking water to remove contamination. While the state has dedicated a large amount of funding and staffing to define the problem and determine a cleanup plan, there is still more work to be done. 

Environmental cleanups take time and sometimes conclude with low level residual contamination remaining. During and after long term cleanup efforts the goal is to provide notice to current and future property owners of the presence of contamination and in some cases also restrict certain property uses that would result in exposure to contamination.

The U.S. EPA designated the Highway 100 and County Road 3 site as a federal Superfund site in September 2020. Placement on the National Priorities List offers access to additional funding needed to investigate and clean up the contaminated area. Costs to identify the source area, pursue potentially responsible parties, and implement a cleanup plan far exceed the funding for the state’s Superfund budget.

In 2025 the EPA initiated a remedial investigation (RI) to better understand the contaminant plume and to identify a contaminant source. Investigations will likely continue throughout 2026, until a source area is confirmed. Once a source area is determined, and the contaminant plume is fully understood, a remedial response will be selected to pursue cleanup of the identified release. If a responsible party is identified as part of this RI, EPA will hold them accountable for the associated impacts and cleanup requirements.