The Janesville Old Landfill covers 18 acres in Rock County, Wisconsin. It operated as a municipal sanitary landfill from 1963 to 1978 on an abandoned sand and gravel pit. The site accepted drummed solvents, oil, paint, paint thinners, and dried sludge from a nearby Superfund site. EPA added it to the National Priorities List in 1984. A residential neighborhood sits about a quarter mile to the east, and the Rock River is 1,500 feet away. No private or municipal drinking water wells lie in the path of the groundwater plume between the landfill and the river.
Groundwater is the affected medium, and EPA has identified 13 contaminants of concern there. They include volatile organic compounds (VOCs) such as 1,1,1-trichloroethane, benzene, vinyl chloride, and dichloromethane. Heavy metals and metalloids found at the site include arsenic, lead, barium, iron, and manganese. Acetone and bis(2-ethylhexyl)phthalate are also present.
Remedial construction was completed on September 18, 1997. The cleanup included a landfill cap, a gas collection and treatment system, and a groundwater treatment system. The original remedy also used groundwater extraction through vertical wells and air stripping. A 1997 modification adjusted the remedy by removing one component and changing groundwater monitoring requirements. These controls remain in place. Natural processes continue to reduce contaminant levels in groundwater, and monitoring is ongoing. A group of companies and the city of Janesville are responsible for the cleanup under a legal agreement. The city monitors and maintains the site. EPA and the Wisconsin Department of Natural Resources oversee and approve the work.
Human exposure is currently under control across the entire site, with no unacceptable exposure pathways. Contaminated groundwater migration has been stabilized, and cleanup goals for current and reasonably anticipated future land uses have been met. The site achieved ready status for anticipated reuse on June 12, 2008, though it has not yet been deleted from the National Priorities List. EPA conducts five-year reviews to confirm the cleanup stays protective. The most recent review was completed on June 24, 2021, with the next one estimated between June and August 2026.
Community members can review site records at the Hedberg Public Library, located at 316 S. Main Street in Janesville. An administrative record with 87 documents is available there. EPA also completed a situation assessment in 2010 that found the site could support community recreation, new industry, wildlife habitat, or a mix of those uses. Questions can be directed to the EPA staff assigned to the site.
