EPA approves the State implementation plan (SIP) revisions submitted by the Governor of Montana with a letter dated November 14, 1997. This submittal consists of several revisions to Missoula County Air Quality Control Program regulations, which were adopted by the Montana Board of Environmental Review (MBER) on October 31, 1997. These rules include regulations regarding general definitions, open burning, and criminal penalties. This submittal also includes revisions to regulations regarding national standards of performance for new stationary sources (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAPs), which will be handled separately.