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Media Contact:

Bonnie Gestring, Earthworks, bgestring@earthworksaction.org, 406.546.8386
Pete Riede, Crow Creek Conservation Alliance, 307.248.0554

As federal agencies consider Simplot’s proposal to expand its Smoky Canyon phosphate mine, independent tests, confirmed by Simplot’s monitoring data, show that trout downstream from the company’s existing Smoky Canyon operations continue to contain harmful levels of selenium–a toxic pollutant that causes birth defects and reproductive failure in fish. Brown trout and Yellowstone Cutthroat trout collected from Sage Creek and Crow Creek downstream of the mine contain selenium concentrations that far surpass the 8.2 mg/kg criteria recommended by the EPA.

Selenium pollution from Simplot’s Smoky Canyon phosphate mine has polluted waterways in southwestern Idaho for over two decades. The problem has become so severe that federal agencies are requiring cleanup under the Superfund program, though that did not prevent the approval of an expansion in 2008. A new water treatment facility installed in upper Sage Creek is only processing half of the contaminated flows. Nevertheless, the Bureau of Land Management and Forest Service are considering yet another expansion of the mine–a plan that does not currently call for any further steps to address the pollution problem. The Final EIS and draft Record of Decision are expected from the Forest Service on July 15, 2019.

“The treatment facility is a step in the right direction, but the pollution continues to flow into our streams and contaminate the trout,” said Pete Riede, a private landowner along Crow Creek and member of the Crow Creek Conservation Alliance. “I hope Simplot sees that they have more work to do on cleanup and prevention.”

The Crow Creek Conservation Alliance and Earthworks have been conducting fish tissue sampling for years, with the assistance of a fisheries biologist. The data from this and previous studies is consistent with results from studies performed by Simplot. Selenium levels at Sage Creek remain roughly four times the EPA criteria and were over 2.5 times the EPA criteria in Crow Creek downstream from Sage Creek.

“Simplot needs to get a handle on its current pollution before it expands once again,” said Bonnie Gestring, northwest program director for Earthworks. “Two decades of pollution is more than the public or any neighbor should have to withstand.”

Once released, selenium can persist in the environment for a very long time. Trout contaminated with selenium are known to give birth to deformed fish.


  • Map of sampling locations and lab results graphs: https://earthworks.org/assets/uploads/2019/05/Selenium_Salt_2018.pdf
  • Photo of yellowstone cutthroat trout. https://www.dropbox.com/s/5jweic0hejtuawa/YellowstoneCutthroat%20%281%29.jpg?dl=0

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