The largest diversified mining corporation in Canada has petitioned environmental regulators in Montana to weaken a new water quality standard at the international border, where for years pollutants have been leaching from the company’s British Columbia coal mines into the Kootenai River basin, including Lake Koocanusa. The company behind the petition, Teck Resources Limited, is solely responsible for the release of mining contaminants into tributaries of B.C.’s Elk River, which enters Montana at the U.S.-Canada border before joining the Kootenai River.