EPA is taking final action to partially approve and partially disapprove portions of a State Implementation Plan (SIP) submission from the State of Montana that are intended to demonstrate that its SIP meets certain interstate transport requirements of the Clean Air Act ("Act" or "CAA") for the 2006 fine particulate matter ("PM<INF>2.5</INF>") National Ambient Air Quality Standards ("NAAQS"). Specifically, EPA is partially approving and partially disapproving the portion of the Montana SIP submission that addresses the CAA requirement prohibiting emissions from Montana sources from significantly contributing to nonattainment of the 2006 PM<INF>2.5</INF> NAAQS in any other state or interfering with maintenance of the 2006 PM<INF>2.5</INF> NAAQS by any other state. EPA is also partially approving and partially disapproving the portion of Montana's submission that addresses the CAA requirement that SIPs contain provisions to insure compliance with specific other CAA requirements relating to interstate and international pollution abatement. These partial disapprovals will not trigger an obligation for EPA to promulgate a Federal Implementation Plan (FIP) to address these interstate transport requirements as EPA is determining that the existing SIP is adequate to meet the specific CAA requirements.