Court upholds stricter selenium standards for Lake Koocanusa

A Montana District Court this week upheld a 2020 state water quality standard for selenium in Lake Koocanusa, dismissing a rule enacted by the state Board of Environmental Review that sought to weaken the standard in 2022.

In the order, Lewis and Clark District Judge Kathy Seeley found that the board no longer has rulemaking authority, which instead resides with the Department of Environmental Quality, and favored the state and a coalition of conservation organizations that sought to preserve the existing standards.

“This decision is a major victory for the communities and fish that depend on a clean Lake Koocanusa watershed,” Shiloh Hernandez, senior attorney with Earthjustice’s Northern Rockies Office, said in a statement. “It is unconscionable that we would allow a coal company to poison one of our most biodiverse and culturally significant watersheds. We are thankful that the Court sided with the EPA, Montana Department of Environmental Quality, and conservation groups in upholding this science-based selenium standard.”

Lake Koocanusa, the 92-mile reservoir bridging the U.S.-Canada border in Northwest Montana, has a selenium standard of 0.8 micrograms per liter, and 3.1 micrograms per liter for the Kootenai River below Libby Dam.

Selenium is a mineral often found in coal-rich deposits, which can be lethal to fish and other aquatic life in high doses, and cause health issues.

A primary source of the selenium found in Lake Koocanusa can be found by tracing its tributary, the Elk River, which enters the reservoir roughly 16 miles north of the U.S. border, into the mountains of British Columbia.

Those mountains are being mined by Elk Valley Resources — formerly owned by Teck Resources and now by international conglomerate Glencore — and the mining operations have caused increases in selenium pollution in the Elk River, according to multiple studies spanning more than a decade. A recent U.S. A Geological Survey study published in 2023 linked the expansion of mining operations with increased selenium and nitrate concentrations over decades, and indicated selenium concentrations in Koocanusa had not met Montana’s site-specific standards since 2020.

Teck was fined $60 million in 2021 for dumping harmful materials into the river and harming westslope cutthroat trout, white sturgeon and other fish populations. Excessive selenium accumulation in fish can lead to detrimental effects including growth inhibition and reproductive impairments.

However, Teck had also lobbied for moderating the site-specific selenium standard in Lake Koocanusa, submitting petitions to the state to weaken the standard, which helped lead to the attempted rule reversal in 2022.

The standards, which are more stringent than national water quality standards, were put in place by the state Board of Review in late 2020, during the administration of former Democratic Gov. Steve Bullock.

The board, a quasi-judicial body, had a changeover in a majority of members during the next years following Republican Gov. Greg Gianforte’s tenure, and in 2022 it reversed its earlier finding, stating that the board had acted “pursuant to a mistake of law.”

However, in the intervening Legislative session in 2021, Montana lawmakers had removed rulemaking authority from the Board of Environmental Review and gave that power to the Department of Environmental Quality.

Legal action was initiated by DEQ in 2023 with a petition for a court to review the bBoard’s rulemaking ability following legislative changes. Several environmental groups, including the Montana Environmental Information Center, the Clark Fork Coalition, the Idaho Conservation League, and the Idaho Rivers United filed a similar petition, which the court consolidated.

In the decision by Seeley, the court focused on the legal ability for the Board of Environmental Review to make rules in 2022, ultimately concluding that such actions were “arbitrary and capricious,” and no longer within the BER’s authority.

“There is no genuine issue of material fact and the legal issue is clear. The Legislature’s statutory change in rulemaking authority effective July 1, 2021, negated any rulemaking action by the BER after that date,” Seelely wrote. “The April 2022 Order is a rulemaking action. The BER did not have the authority to engage in rulemaking.”

The conservation organizations, many of which have been involved in repeated legal actions to uphold the stricter selenium standards, praised the decision by the court.

“We’re happy to see that the Court made the right decision by protecting Montana’s waters from upstream Canadian coal mine pollution,” said Derf Johnson, deputy director for the Montana Environmental Information Center. “Montana’s water quality standards for selenium are based in science. Not only do they protect our water quality, but they also protect wildlife and the outdoor recreation economy that depends on clean water.”

Selenium pollution in Lake Koocanusa has been a concern for both the U.S., Canada and tribal nations in the region for years, with the transboundary Ktunaxa nation raising concerns about water quality in 2012 and the British Columbian government subsequently ordering the mining companies to stabilize and reduce contaminants leaching into the Elk River.

In 2024, the International Joint Commission, an organization created by the United States and Canada to resolve disputes related to shared waterways, convened a board of experts to study the issue of transboundary pollution in the Elk-Kootenai River Basin. The commission’s plan of study, released last March, outlines a series of objectives for the board including collecting and analyzing data on water quality and pollutants, determining impacts to ecosystems and human health, and identifying possible mitigation and remediation efforts.

A preliminary report is expected this fall with a final report to the IJC provided in September 2026.

Elk Valley Resources has proposed expanding one of its coal mines in the area and earlier this year British Columbia’s Environmental Assessment Office (EAO) has began its environmental review of the plans.