Hechimovich Sanitary Landfill is a 24-acre former municipal and industrial waste site in Williamstown, Wisconsin. It operated from 1959 to 1986, accepting hazardous and liquid industrial wastes placed in unlined pits. The site was added to the National Priorities List (NPL) in March 1989. NPL is the federal list of the most serious contaminated sites in the country. Physical construction of the cleanup finished in September 1997, and the most recent five-year review, completed in May 2024, found the cleanup continues to protect public health and the environment.
The site is split into two operable units, which are separate portions of a site addressed by distinct cleanup plans. The first unit required no further action beyond the initial work. The second unit relies on institutional controls, monitored natural attenuation (allowing natural processes to reduce contamination over time), and a gas collection and treatment system. Groundwater contamination includes 1,2-dichloroethane, chloroethene (also known as vinyl chloride), and trichloroethane. These chemicals were found in groundwater and pose unacceptable risks to human health or the environment. A wetland directly north of the site could also be at risk from site runoff.
A significant development came in 2009 when deeper groundwater contamination was discovered in bedrock, moving northeast off the landfill property and reaching two private drinking water wells. The source appears to be a heavy liquid chemical mixture that sank into the groundwater and has since dissolved, continuing to move with the water flow. As an interim measure, bottled water was provided to affected homes where contamination exceeded drinking water standards. One home received a treatment system on its existing well, with monthly monitoring ongoing. Future response actions are expected to focus on monitoring and protecting water supplies, as active source cleanup appears unlikely.
EPA's performance measures show that human exposure is currently under control, with no unacceptable exposure pathways identified. Groundwater migration is also under control, with no unacceptable discharge to surface water expected. The site has not been deleted from the NPL and has not yet achieved sitewide readiness for anticipated reuse, meaning some cleanup goals or required controls are not fully met. The next five-year review is scheduled for 2029.
Community members with questions can contact the EPA's Community Involvement Coordinator or Remedial Project Manager. For technical hydrogeology questions, contact the Wisconsin Department of Natural Resources.
