Pollution from a phosphate mine in southeast Idaho and near Star Valley is causing deformities in fish populations, including two-headed trout, conservation groups say.

Images of two-headed cutthroat trout and other deformed fish come from a 1,200-page report by J.R. Simplot Company that the company produced in an attempt to skirt Idaho Department of Environmental Quality selenium pollution rules, said Marv Hoyt, Idaho director of the Greater Yellowstone Coalition. The fish were found in tributaries of the Salt River, which drains into Palisades Reservoir.

Simplot officials deny knowledge of the photographs.

The element selenium is a byproduct of phosphate mining. The element is an essential human nutrient in small doses but is a known toxin at higher doses. Selenium has been blamed for a number of livestock die-offs near phosphate mines in southeast Idaho, including 600 sheep and 18 head of cattle, Hoyt said.

The deformed fish come from Sage Creek and Crow Creek near the Smoky Canyon Mine, about 10 miles west of Afton, Hoyt said. Crow Creek is one of the major tributaries of the Salt River.

The Smoky Canyon Mine is a Superfund site, and Simplot hoped the report would help the company avoid paying the “tens of millions of dollars to clean it up,” Hoyt said.

Just before the U.S. Fish and Wildlife Service, the Environmental Protection Agency and the Idaho Department of Environmental Quality signed off on the Simplot report, U.S. Fish and Wildlife Service biologist Joseph Skorupa reviewed the document and found serious problems, Hoyt said. Skorupa, an expert on selenium pollution, found that “in a nutshell, [Simplot scientists] misapplied a lot of the data, they failed to appropriately use … models and therefore, their conclusions are very questionable,” Hoyt said.

Indeed, in a 154-page critique entitled Technical Review: Smoky Canyon Mine Site-Specific Selenium Criterion Report, Skorupa found Simplot researchers underestimated how many fish would be deformed in waters adjacent to the Smoky Canyon Mine. The research on trout was “systematically biased low and [used an] environmentally unrealistic quantification of larval deformity rates,” Skorupa said in his critique. In other parts of the critique, Skorupa calls specific techniques used by the Simplot researchers “highly questionable” and said they used “confounded data.” Simplot refused to supply raw data for Skorupa to review, he reported. Three independent peer reviewers agreed with more than 94 percent of Skorupa’s conclusions.

Skorupa’s review shows there were more deformities than Simplot researchers were willing to admit, Hoyt said. “There were literally hundreds and hundreds of deformities in fish subjected to selenium concentrations in those streams, streams that are directly affected by the Smoky Canyon phosphate mine,” he said.

Simplot officials denied knowledge of two-headed fish.

“We’re not aware of any two-headed fish near our facilities,” Simplot spokesman David Cuoio said. “I’m not sure who took those pictures or where they were taken.”