American Rivers
American Rivers

Protect the Clark Fork River from Harmful Toxins - Demand Cleanup

Clark Fork River | Photo by Chris Boyer / Kestrelaerial

Do you remember last year’s catastrophic flooding on the Yellowstone River? Every spring the water rises on the Clark Fork, and runoff threatens to wash toxic industrial chemicals from the shuttered Smurfit-Stone pulp mill into the river and downstream.  

For more than 50 years, the Smurfit-Stone mill generated a staggering amount of hazardous waste containing dioxins and heavy metals. Much of that waste is still onsite – strewn across 1,000-acres right next to the Clark Fork River. Within that toxic area, roughly 140-190 acres of unlined sludge ponds and landfills pose the greatest health risks. Not only are they leaking toxic chemicals into the groundwater that flows to the river, the only thing separating much of this wasteland from the river is an uncertified, unmaintained four-mile-long earthen berm. In 2018, spring runoff pounded this porous berm for weeks, releasing a plume of dark arsenic-laced water and forcing emergency construction to prevent a breach.

Last year, the Yellowstone River experienced a 500-year flood, with devastating results for riverside homes and public infrastructure. When will catastrophic flooding happen on the Clark Fork? We don’t know when, but we know it will happen.

That is why American Rivers is including the Clark Fork River on its list of America’s Most Endangered Rivers® of 2023. After the mill closed in 2010, the Environmental Protection Agency (EPA) placed the Smurfit-Stone mill on its inventory of Superfund sites. After 13 years of runoffs, berm decay, and hazardous waste trickling into the river, it’s time for EPA to do right by the river – and the people, fish, and wildlife it sustains – and direct the responsible parties to honor their financial obligations and clean up their toxic mess.

The Clark Fork flows 320 miles from its headwaters along the Continental Divide in Butte to Lake Pend Oreille in Idaho, supplying local communities throughout western Montana with drinking water, irrigation for farms and ranches, and opportunities to interact with nature. Efforts to tackle legacy mining contamination in the headwaters have made important headway over the years and are ongoing. However, downstream pollution at the Smurfit-Stone mill threatens these hard-fought upstream successes. The EPA’s remedial investigation as part of the Superfund cleanup process has languished, despite compelling evidence to begin early cleanup of the sludge ponds and landfills – the most polluted portion of the entire site.

The risks of flooding are real. The community’s vision for cleanup is clear. Please join us in demanding that EPA take action to eliminate a serious threat to the Clark Fork by cleaning up the contaminated sludge ponds and landfills, removing the berm, and restoring the floodplain at the Smurfit-Stone mill site.

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Region 8 Administrator
U.S. Environmental Protection Agency