Montana Second 10-Year Carbon Monoxide Maintenance Plan for Missoula

The Environmental Protection Agency (EPA) is proposing to approve a State Implementation Plan (SIP) revision submitted to the EPA by the State of Montana. On September 19, 2016, the Governor of Montana's designee submitted a Clean Air Act (CAA) section 175A(b) second 10-year limited maintenance plan for the Missoula area for the carbon monoxide (CO) National Ambient Air Quality Standard (NAAQS). This limited maintenance plan addresses maintenance of the CO NAAQS for a second 10-year period beyond the original redesignation. This action is being taken under sections 110 and 175A of the CAA.