Approval and Promulgation of Air Quality Implementation Plans; Montana; Revisions to Administrative Rules of Montana-Prevention of Significant Deterioration

The Environmental Protection Agency (EPA) is taking final action to approve State Implementation Plan (SIP) revisions submitted by the State of Montana on June 4, 2013. This submission revises the Administrative Rules of Montana that pertain to the issuance of Montana air quality permits. The June 4, 2013 revisions contain amended and renumbered rules that, among other things, address the proper treatment of air pollutants under the State's prevention of significant deterioration (PSD) program. In this rulemaking, we are taking final action on all of the June 4, 2013 submittal, with the exception of one small portion. This action is being taken under section 110 of the Clean Air Act (CAA).