Montana Department of Environmental Quality About Us Permitting & Operator Assistance Public Participation

Air Quality | State Implementation Plan Revision | Public Comment Ends July 25, 2026

  • June 26 2026

The 2021 legislature passed Senate Bill 233, reassigning and transferring the rulemaking duties and powers of the Board of Environmental Review (BER) to the Department of Environmental Quality (DEQ).

Senate Bill 233 also repealed §§ 75-6-103, 75-10-106, 82-4-111, and 82-4-204, Montana Code Annotated (MCA) so citations in the appropriate rules were renumbered to account for the MCA sections that had been repealed by Senate Bill 233.

The 2025 legislature amended section 75-2-109 MCA, repealing sections 2-15-2110 and 75-2-106 MCA, eliminating the Small Business Compliance Assistance Advisory Council from the Clean Air Act of Montana (MT CAA). The Small Business Stationary Source Representative, instead of a council, will consult with small businesses and other stakeholders.

DEQ is inviting public comments on its proposal to revise the State Implementation Plan (SIP) to align with these legislative actions. Public comments will be accepted from Thursday, June 25th until 11:59 p.m. July 25, 2026. If DEQ receives a request for public hearing, a public hearing on this matter will be scheduled, the time for that hearing will be announced, and an additional 30-day time period for submitting comments will be scheduled. All comments received will be included when the SIP revision is reviewed and submitted to the EPA.

DEQ will make reasonable accommodations for people with disabilities who wish to participate in this SIP revision process or need an alternative accessible format of this notice. If you require accommodation, contact the department no later than 5:00 p.m. on July 15, 2026, to advise us of the nature of the accommodation that you need. Please contact the Department of Environmental Quality at P.O. Box 200901, Helena, Montana 59620-0901; phone (406) 444-3490; or e-mail deqair@mt.gov .

 

Associated Materials: 

MAR Notice No. 17-432A: Issue 18 of the 2023 MAR on pages 1054 – 1058

MAR Notice No. 17-451: Issue 4 of the 2024 MAR on pages 2576 - 2578

MCA Title 75, Chapter 2, Part 1 small changes to (2)(b) and (h)

 

Comment Period Ends:

  • Saturday July 25, 2026, at 11:59 p.m.

 

Send Comments To:

Written comments can be submitted to DEQ through the following options:

  • Mail to :

        DEQ Air Quality Bureau Planning Section
        P.O. Box 200901
        Helena, Montana 59620-0901

OR

  • Email to:

        DEQ Air Quality Analysis & Planning Section 

Tags: Public Comment and Air