The Smurfit-Stone Mill site covers about 3,200 acres near Frenchtown, Montana, where a paper and pulp mill ran from 1957 until 2010. The U.S. Environmental Protection Agency (EPA) proposed the site for the National Priorities List (NPL), the federal list of the most serious hazardous waste sites, in 2013, though it has not yet been formally added. The site is divided into three operable units (OUs), which are distinct cleanup areas. OU1 covers roughly 1,200 acres of agricultural land. OU2 encompasses the 255-acre former mill core. OU3 includes about 1,700 acres of former wastewater treatment land and Clark Fork River floodplain.
Key contaminants include PCBs (polychlorinated biphenyls), dioxins and furans, arsenic, manganese, and chromium. These have been detected in soil, groundwater, surface water, and river sediment. A 2017 assessment found OU1 poses no human health concern. Assessments completed in 2021 and 2022 for OU2 and OU3 found risks to hypothetical future residents from arsenic and manganese in groundwater and chromium in soil. Both recreational and Tribal fishers face unacceptable risks from eating fish in the Clark Fork River near the site, driven mainly by PCBs and dioxins. Montana Fish, Wildlife and Parks has a fish consumption advisory in place for the Clark Fork River in that area.
Cleanup actions taken so far include groundwater sampling, soil testing, fish studies, berm inspections, and a railroad removal action. An Administrative Order of Consent for one sitewide OU was finalized in November 2015, and remedial investigation work began that same month. A second Administrative Order of Consent was completed in February 2021, followed by EPA-overseen removal work from May 2021 through September 2023. In 2023 and 2024, EPA directed additional sampling for sediment, groundwater, surface water, and soil in response to community concerns about PCBs. Final data from that work came in during July and August 2025 and will be included in the upcoming Remedial Investigation report. The site is privately owned, except for the Clark Fork River, and no formal EPA-enforced institutional controls have been imposed through the Superfund process yet.
Community members can get involved through the Community Advisory Group (CAG), which meets on the first Thursday of each month at 6 p.m. at the Frenchtown Rural Fire District and online. The CAG connects residents with EPA and the Montana Department of Environmental Quality (DEQ). EPA also holds stakeholder meetings, conducts local business outreach, and publishes fact sheets and monthly progress reports. Site records are available at the EPA Superfund Records Center in Helena and at the Frenchtown Rural Fire District Hall.
