MT HB291

Montana Department of Environmental Quality prohibited from adopting air quality rules more stringent than federal Clean Air Act standards, eliminating the previous process that allowed stricter rules with public hearing and scientific justification

Local air pollution control programs similarly restricted from adopting standards exceeding state or federal requirements, removing prior provisions that permitted more stringent local rules with documented health/environmental findings

Existing air pollutant emission requirements established before the act's effective date remain valid and enforceable

Exception preserved for areas classified as nonattainment or maintenance under federal air quality standards, where stricter measures may still be necessary to comply with national ambient air quality requirements

Act takes effect immediately upon passage and approval, amending sections 75-2-111, 75-2-203, 75-2-207, and 75-2-301 of Montana Code Annotated