Ripon City Landfill

Overview

Ripon City Landfill is a 7-acre former gravel pit in Fond du Lac County, Wisconsin. It accepted municipal and commercial waste from 1968 to 1983. That waste contaminated groundwater beneath the site. The EPA added the landfill to the National Priorities List in 1994, which triggered a formal federal cleanup process.

Five chemicals have been found in groundwater at the site. They are benzene, chloroethene (vinyl chloride), cis-1,2-dichloroethene, tetrachloroethene, and trichloroethene. The EPA determined that all five pose an unacceptable risk to human health or the environment based on the amounts present and the potential effects of exposure. The main concern is people ingesting or contacting contaminated groundwater.

The Wisconsin Department of Natural Resources selected a cleanup plan in 1996 with EPA support. Crews completed physical construction of the landfill remedy in September 1996. The cleanup included placing a plastic membrane and soil cap over the entire landfill, installing a gas venting system, putting up fencing, and applying a deed restriction to prevent disturbance of the cap. A five-year review finished in August 2021 found the cleanup is protective of people and the environment in the short term. However, long-term protection requires enhanced gas extraction, cleanup of the contaminated groundwater plume, and an alternative water supply. In 2024, the Wisconsin Department of Natural Resources approved a passive gas pilot study to see whether passive extraction alone can keep gas levels under control. A Record of Decision Amendment for the groundwater portion of the site is estimated between March and May 2028.

Human exposure to site contaminants is currently under control, meaning no unacceptable exposure pathways exist at this time. Even so, the site has not yet achieved cleanup goals for all land uses, and groundwater monitoring continues. The EPA is now conducting its sixth five-year review, expected to be complete by Summer 2026.

Community members can learn more by visiting the Ripon Public Library at 120 Jefferson Street in Ripon, Wisconsin, where public records related to Superfund work at the site are available. Questions can also be directed to the EPA staff assigned to the site.