A fly fisherman casts on the Kootenai River, downstream of the Koocanusa Reservoir at the centre of the dispute, near the Montana-Idaho border and Leonia, Idaho, on Sept. 19, 2014. The U.S. government is increasingly concerned with pollution from British Columbia mines following new research that shows contaminants in a river south of the border came from Canada. In a letter obtained by The Canadian Press, the Environmental Protection Agency is demanding the provincial government hand over data explaining why Teck Resources coal mines in southern B.C are being allowed to exceed guidelines for a toxic heavy metal. "The EPA ... finds it unacceptable that the province has accepted (a treatment plan) that will allow seasonal exceedances of water quality objectives into the future," says the Feb. 4 letter to Environment Minister George Heyman. "An independent review could help facilitate U.S. stakeholder confidence in this new approach." Contamination from Teck's mines in the rivers of the Elk River watershed is a long-standing problem. Coal mining releases selenium, an element which in large amounts is toxic to wildlife and humans. THE CANADIAN PRESS/AP - The Spokesman Review, Rich Landers

A fly fisherman casts on the Kootenai River, downstream of the Koocanusa Reservoir at the centre of the dispute, near the Montana-Idaho border and Leonia, Idaho, on Sept. 19, 2014. The U.S. government is increasingly concerned with pollution from British Columbia mines following new research that shows contaminants in a river south of the border came from Canada. In a letter obtained by The Canadian Press, the Environmental Protection Agency is demanding the provincial government hand over data explaining why Teck Resources coal mines in southern B.C are being allowed to exceed guidelines for a toxic heavy metal. "The EPA ... finds it unacceptable that the province has accepted (a treatment plan) that will allow seasonal exceedances of water quality objectives into the future," says the Feb. 4 letter to Environment Minister George Heyman. "An independent review could help facilitate U.S. stakeholder confidence in this new approach." Contamination from Teck's mines in the rivers of the Elk River watershed is a long-standing problem. Coal mining releases selenium, an element which in large amounts is toxic to wildlife and humans. THE CANADIAN PRESS/AP - The Spokesman Review, Rich Landers