An iron works facility operated at Tar Lake from 1882 to 1945, disposing of industrial waste into a 4-acre pond and the surrounding 234 acres in Mancelona Township, Michigan. EPA added the site to the Superfund National Priorities List (NPL) in September 1983. The site is divided into operable units to manage cleanup in stages, and two areas totaling 120 acres have already been removed from the NPL after meeting cleanup standards.
More than 50 chemicals contaminate soil and groundwater at the site. These include metals such as arsenic, cadmium, chromium, copper, lead, nickel, and silver. Organic chemicals include benzene, toluene, ethylbenzene, xylene, styrene, tetrachloroethene, and trichloroethene. Polycyclic aromatic hydrocarbons, phenol and cresol compounds, phthalates, and ketones round out the list. Human exposure is currently under control, but contaminated groundwater migration has not yet been stabilized.
Early cleanup actions included excavating tar and contaminated soils, extracting and treating groundwater, and placing activity restrictions on the site. A remedy for the 196-acre manufacturing facility was selected in 2002, and construction was completed in 2004. In 2013, EPA determined that additional soil excavation and expanded groundwater treatment were needed. The cleanup design was finished in 2018 and revised in 2024 due to changing groundwater conditions. Remedial action activities began in July 2024 with support from Bipartisan Infrastructure Law funds, and the main cleanup work is expected to start in spring 2026.
EPA's most recent five-year review, completed in August 2024, confirmed that current measures protect public health in the short term. Long-term protection requires completing the additional remedies proposed in 2013. Those steps include investigating private drinking water wells, conducting a PFAS (per- and polyfluoroalkyl substances) contamination study, and expanding the biosparge groundwater treatment system, which uses microbes to break down contaminants. A partial NPL deletion is estimated between August and October 2027. Commercial businesses and a municipal wood waste storage area currently operate on portions of the site, and institutional controls limit land uses such as residential development to reduce exposure to remaining contamination.
Community members can review site records at the Mancelona Township Library at 202 West State Street in Mancelona, Michigan. An updated Community Involvement Plan issued in October 2018 explains how residents and stakeholders can stay informed and participate in cleanup decisions. Questions can be directed to EPA's Community Involvement Coordinator or to other EPA and Michigan state staff assigned to the site.
