DEQ Releases Final Greenhouse Gas Guidance Document

The Montana Department of Environmental Quality (DEQ) has released the final guidance document to instruct state agencies when conducting analyses as part of the Montana Environmental Policy Act (MEPA) regarding greenhouse gas emissions (GHG). 

 

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 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. 

 

The public comment period for the draft GHG guidance was held from October 1 -30, 2025, and DEQ held three public listening sessions to receive public comment. The final guidance document was revised based on constructive feedback from the public in two major ways. DEQ refined its model to assess impacts in aggregate instead of individual projects. Additionally, the final guidance includes mitigation and alternatives for MEPA. 

 

The final guidance document can be found on DEQ’s website.