Montana Environmental Policy Act

The Montana Environmental Policy Act (MEPA) was established by the State Legislature in 1971. MEPA is procedural and does not control or set regulations for any specific land or resource use. Instead, MEPA establishes processes for environmental impact review, analysis, and public participation. MEPA also established the Environmental Quality Council (EQC) as a statutory arm of the Legislature to provide continuing oversight and guidance for environmental legislation.

In the 2025 Session, the Legislature reformed MEPA by passing Senate Bill 221, which directed DEQ to create a guidance document for state agencies to use as a resource when gathering information about greenhouse gas (GHG) emissions. Agencies gather this information while conducting an Environmental Assessment (EA) or an Environmental Impact Statement (EIS). These assessments are informational and cannot be used to regulate or deny permits. The document recommends methodologies for complying with MEPA.  

GHG emissions are gases, such as carbon dioxide, methane, nitrous oxide, and fluorinated gases that are released into the atmosphere. Final GHG Guidance materials were published in January 2026.

• Final GHG Guidance
• Appendix 1 Ecological Functions
• Appendix 2 Secondary Impacts of GHG
• Appendix 3 Methods and Means of Quantifying Costs Related to GHG Emissions
• Appendix 4 Cumulative Impacts of GHG

On September 27, 2023, the Department of Environmental Quality (DEQ) kicked off an effort to thoughtfully review implementation of MEPA.

As part of this effort, DEQ held four public listening sessions and opened a comment portal to hear creative suggestions and feedback from Montanans familiar with the MEPA process. Montanans were invited to share their thoughts about MEPA implementation, and many responded. The comments received will inform ongoing conversations and serve as the foundation for work to be completed over the first half of 2024 by a diverse stakeholder group.

View Public Comments Final Report

In October 2023, DEQ began a series of public listening sessions to gather input on the MEPA process, implementation, intent, and potential need for updates to the statutes or implementing rules. These sessions accompanied an open public comment opportunity.

Following a productive series of listening sessions and public comment opportunities in Phase I, DEQ continued the conversation with a diverse group of MEPA experts. 

The work group met regularly throughout the first half of 2024. Meetings were open to the public and provided opportunities for public comment. Following the work group’s deliberations, DEQ presented a comprehensive report summarizing the conversation and offering actionable recommendations.