Public Notice: EPA Begins 7th Review of Wausau Groundwater Contamination Superfund Site

Summary

The U.S. Environmental Protection Agency is conducting its 7th five-year review of the Wausau Groundwater Contamination Superfund site in Wausau, Wisconsin. The Superfund law requires regular checkups of sites that have been cleaned up, with waste managed on-site, to make sure the cleanup continues to protect people and the environment. This review is expected to be completed in April 2025.

The site consists of two contaminant source areas separated by the Wisconsin River. The eastern portion of the site is related to solvent spills from the former Wausau Chemical facility, and the western portion is related to the former City of Wausau landfill.

EPA’s cleanup of volatile organic compounds at the site consisted of several extraction wells and treatment systems, two soil vapor extraction systems, a landfill cover over the waste area, land and groundwater-use restrictions, and groundwater monitoring.

In 2020 during the previous five-year review, the EPA deferred protectiveness of the remedy due to a lack of vapor intrusion data. The EPA expects to make a protectiveness determination in 2028 after testing.

In 2023 and 2024, the EPA oversaw vapor intrusion sampling at commercial buildings which were identified as potential vapor intrusion risks based on their proximity to source areas or elevated groundwater concentrations. Results did not show any health risks related to vapor intrusion, except for one indoor air exceedance.

In March 2024, the EPA released a significant modification to the existing site remedy in order to protect human health and the environment. The change imposes additional municipal ordinances and land use restrictions, which are documented in an Explanation of Significant Differences. More information is available online at www.epa.gov/superfund/wausau-groundwater and at the Marathon County Public Library, 300 N. First St., Wausau.