MT DEQ Seeks Public Input on Draft Greenhouse Gas Guidance

The Montana Department of Environmental Quality (DEQ) is inviting public comment on a new draft guidance document that outlines how state agencies should evaluate greenhouse gas (GHG) emissions under the Montana Environmental Policy Act (MEPA).

The 86-page draft, released on October 1st, was developed after the passing of Senate Bill 221 during the 2025 Legislative Session. SB221 directs the Montana DEQ to create standardized procedures for when and how agencies must assess greenhouse gas impacts during environmental reviews.

Most notably, the document follows the landmark cases of Held v. State of Montana (2024) and MEIC v. DEQ (2025). The former reaffirmed the constitutional right of Montanans to a “clean and healthful environment,” while the latter required state agencies to consider greenhouse gas emissions in major permitting decisions.

DEQ’s draft guidance details when GHG assessments are required—particularly for fossil fuel projects—and provides technical methods for estimating emissions, including use of EPA calculators and models to quantify both direct and cumulative impacts. It also includes four appendices addressing ecological functions, secondary impacts, cost quantification, and cumulative effects.

Public input will be accepted through Oct. 30. Comments can be senComments can be sent to DEQ’s MEPA program, Attention: Craig Jones, P.O. Box 200901, Helena, MT 59620-0901.O. Box 200901, Helena, MT 59620-0901, or emailed to deqmepa@mt.gov.

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DEQ will also host three listening sessions later this month:

Billings: Oct. 27, 6–8 p.m., Billings Hotel and Convention Center

Missoula: Oct. 29, 6–8 p.m., University Center South Ballroom, University of Montana

Helena: Oct. 30, 6–8 p.m., Delta Hotel