EPA is acting on revisions to the State Implementation Plan (SIP) submitted by the Governor of Montana on May 17, 1994. The submittal included, among other things, revisions to the State's construction permitting regulations to comply with Federal requirements and revisions to address outstanding rule deficiencies, as well as a request that the existing regulations in the SIP be replaced with the October 1979 recodification of the Administrative Rules of Montana (ARM). EPA is approving all of the regulations included in this submittal, with the exception of the two director's discretion provisions regarding hydrocarbon emissions which EPA is disapproving, the odor control rules and the sulfur oxide rules for lead smelters on which EPA is taking no action, and the variance provisions which EPA will be acting on in a separate notice. Also, EPA is not approving the submitted versions of two provisions of the State's open burning rules which EPA previously disapproved. The previously-approved versions of these rules remain part of the SIP. In addition, EPA is only partially approving the State's nonattainment permitting rules for the Kalispell PM-10 nonattainment area. Last, EPA is approving Montana's construction permit rules for sources of hazardous air pollutants under section 112(l) of the Clean Air Act.