Montana DEQ Accepting Public Comment on Second Supplemental EA for Yellowstone County Generating Station

HELENA—On Monday (August 24) the Montana Department of Environmental Quality (DEQ) released a second draft supplemental environmental assessment (EA) under the Montana Environmental Policy Act (MEPA) for the Yellowstone County Generating Station, commonly referred to as the Laurel Generating Station, a natural-gas-fired power plant near Laurel, Montana. Public comment will be accepted on the second draft supplemental EA through September 23, 2026.

This second draft supplemental EA is the result of several legal challenges regarding the air quality permit for the Yellowstone County Generating Station. DEQ issued the original final EA and air quality permit for the Yellowstone County Generating Station in 2021. After conservation groups challenged the 2021 EA, the Montana Supreme Court affirmed DEQ’s decision on every issue except greenhouse gas emissions and lighting impacts. To address the Court’s concerns, DEQ issued a new Supplemental Final EA in August 2025.

After DEQ issued the 2025 Supplemental Final EA for the Yellowstone County Generating Station, in January of 2026, DEQ released its Greenhouse Gas Guidance Document. The guidance is a legislatively mandated document that sets forth the process and methodology that DEQ uses to evaluate greenhouse gas and climate impacts under MEPA.

In an additional legal challenge concerning the 2025 EA for the Yellowstone County Generating Station, DEQ and the plaintiffs entered an agreement allowing DEQ to modify its previous 2025 supplemental EA to consider DEQ’s Greenhouse Gas Guidance Document. The resulting document is the second draft supplemental EA for the Yellowstone County Generating Station.

To view the second draft supplemental EA and learn how to comment, please visit DEQ’s website.