For Immediate Release: Friday, May 10, 2024


Will Tiedemann, Conservation Associate, Idaho Conservation League (208) 345-6933 x 213 

Bryan Hurlbutt, Staff Attorney, Advocates for the West, (208) 342-7024 x 206

Will Shoemaker, Communications & Engagement Director, Advocates for the West, (208) 801-7523

Permit invalid for proposed Stibnite Gold Mine over arsenic air pollution concerns

BOISE, ID – On Thursday, May 9, 2024 the Idaho Board of Environmental Quality issued a decision invalidating Perpetua Resources’ air pollution permit for the proposed Stibnite Gold Mine in Valley County. Blasting and hauling operations at the proposed mine would emit massive amounts of arsenic-laden dust. The Board found that the Department of Environmental Quality (DEQ) failed to follow Idaho air pollution rules designed to protect people from exposure to toxic and carcinogenic pollutants when it issued a permit to Perpetua. 

The Idaho Conservation League and the Nez Perce Tribe, represented by Advocates for the West, together with Save the South Fork Salmon, appealed the permit in 2022 after DEQ dismissed repeated concerns during the permitting process.

The Board of Environmental Quality first announced the decision at a May 1 meeting. Speaking on behalf of the Board, member Dr. J. Randy MacMillan stated, “DEQ created a misleading risk analysis that greatly underestimates the actual cancer risk.” 

In Thursday’s written decision, the Board faulted DEQ for employing each of three unreasonable methods to mask the full risk of arsenic exposure caused by the proposed Stibnite Gold Mine. The Board ruled in favor of DEQ and Perpetua on other issues. 

“Arsenic is a toxic pollutant and a carcinogen,” said Bryan Hurlbutt, staff attorney at Advocates for the West. “The Board’s decision sends a strong message. Perpetua cannot bend the rules and disregard the risks from its proposed mine.”

In reaction, Will Tiedemann, a regulatory conservation associate with the Idaho Conservation League, explained, “DEQ incorrectly viewed the mine’s carcinogenic effects of arsenic from a long-term perspective only. Instead, Idaho’s rules require the public to be protected from arsenic on a year by year basis. DEQ’s flawed arsenic emissions analysis is kind of like taking the amount of arsenic a facility could emit each year over 70 years and then allowing that same amount to be emitted in just 16 years.” 

The Board decision remands Perpetua’s air pollution permit, sending it back to the administrative hearing officer to reconsider arsenic emission and cancer risks from the proposed mine. Any party can seek reconsideration before the Board or challenge the Board’s decision in state court. 

DEQ was the first agency to issue any permit of note for the Stibnite Gold Mine. Perpetua is still seeking approvals from the Forest Service and other state and federal agencies. The proposed mine would consist of three open-pits, a massive waste rock dump site, and an extensive network of roads and other infrastructure in the remote headwaters of the East Fork of the South Fork of the Salmon River. 

On a related note, a Hearing Officer with the Idaho Department of Water Resources (IDWR) recently issued a decision approving Perpetua’s water rights for the proposed mine but also imposing important new conditions to better protect the environment. The Idaho Conservation League, Save the South Fork Salmon, and the Nez Perce Tribe had protested Perpetua’s water right application due to the negative impacts of water withdrawals to Chinook salmon, Snake River steelhead, and bull trout. Members of the public also raised concerns that granting the requested water right was not in the public interest. 

The IDWR Hearing Officer responded by applying several terms and conditions to better protect fisheries resources by establishing minimum stream flows in the Meadow Creek and the East Fork South Fork Salmon River from Meadow Creek, through Perpetua’s proposed tunnel, and down to the confluence with Sugar Creek. Perpetua has subsequently asked IDWR to revise or eliminate all the new conditions placed on the permit designed to protect fisheries. IDWR is currently scheduled to issue a final order on July 3.


ICL’s mission is to create a conservation community and pragmatic, enduring solutions that protect and restore the air you breathe, the water you drink, and the land and wildlife you love.

Advocates for the West is a non-profit, public interest environmental law firm headquartered in Boise, Idaho, that works to defend public lands, water, fish and wildlife throughout the American West. Visit Advocates for the West online at