Canada's largest coal company is challenging a new Montana water quality standard that aims to limit concentrations of toxic runoff from the company's mines in British Columbia as it travels across the international border into the Kootenai River and Lake Koocanusa.

Teck Resources Ltd. this month filed a petition with the state Board of Environmental Review, part of the Department of Environmental Quality, which last year adopted a stringent site-specific water quality standard for the trace element selenium, a byproduct of coal mining that's been found at high levels in fish tissue and egg samples on both sides of the border.

At high concentrations, selenium can kill fish, cause reproductive problems and inhibit growth.

Montana's site-specific standard targets Teck's mountaintop-removal coal mines in B.C.'s Elk Valley, which are the sole industrial source of selenium runoff in the region. It allows for selenium concentrations of 0.8 microgram per liter in Lake Koocanusa and 3.1 micrograms per liter in the Kootenai River, though it's difficult to enforce without an equally stringent standard in place in B.C.

The U.S. Environmental Protection Agency in 2016 generally recommended selenium limits of 1.5 micrograms per liter for lakes and reservoirs and 3.1 micrograms per liter for rivers, but also said state regulators should impose site-specific standards where appropriate.

Now, Teck is asking the Board of Environmental Review to nullify the new standard on grounds that it's "more stringent than the comparable federal guideline for selenium of 1.5 micrograms per liter," allegedly in violation of state law.

"Teck reserves, and by filing this petition does not waive, any of its legal rights and causes of action, including but not limited to those based on Montana's lack of jurisdiction to enact a water quality standard targeting Teck's Elk Valley operations," the company's petition warns.

The Board of Environmental Review considered the petition but took no action during its Aug. 13 meeting, with members questioning whether the matter fell within the board's jurisdiction. The board opted to solicit public comments on the administrative procedure before its Oct. 8 meeting.

During the meeting, DEQ attorney Kurt Moser said the agency planned to file paperwork opposing Teck's petition, noting "the board has already concluded that the selenium standards that were adopted were not more stringent than federal." A DEQ spokesman on Friday confirmed the agency still plans to intervene.

Board member David Lehnherr said it would be "a waste of the board's time" to revisit the matter and allow Teck to seek a way around the new rules.

"This issue was dealt with last year, and came to a very scientifically sound conclusion that was in the best interests of Montana and its waterways, and now we have a corporation trying to circumvent the DEQ," Lehnherr said during the meeting. "And so I would say we should just do whatever we can to avoid further involvement with this case, and let the good judgment that the board made last year stand."

In April, Teck paid $60 million in fines after pleading guilty in Canadian federal court for discharging hazardous amounts of selenium and calcite into the Fording River from two coal mines north of Eureka. The pollution was blamed for killing huge numbers of westslope cutthroat trout.

Teck President Don Lindsay apologized at the time and took responsibility for the damage, saying the company had invested about $1 billion in water treatment facilities and pledged to spend up to $655 million more over the next four years to further protect nearby waters.

"Again, to the Ktunaxa First Nation, whose territory we operate on, and to our communities in the Elk Valley, we deeply regret these impacts and we apologize," Lindsay said at the time. "You have my commitment that we will not waver in our focus on addressing this challenge and working to ensure that the environment is protected for today and for future generations."

The $60 million fine was 10 times as large as any previous punishment imposed under Canada's Fisheries Act.