Approval and Promulgation of State Implementation Plan Revisions; Infrastructure Requirements for the 1997 8-Hour Ozone National Ambient Air Quality Standard; Montana

EPA is partially approving and partially disapproving the State Implementation Plan (SIP) submission from the State of Montana to demonstrate that the SIP meets the requirements of Sections 110(a)(1) and (2) of the Clean Air Act (CAA) for the National Ambient Air Quality Standards (NAAQS) promulgated for ozone on July 18, 1997. Section 110(a)(1) of the CAA requires that each state, after a new or revised NAAQS is promulgated, review their SIPs to ensure that they meet the requirements of the "infrastructure elements" of section 110(a)(2). The State of Montana submitted two certifications, dated November 28, 2007 and December 22, 2009, that its SIP met these requirements for the 1997 ozone NAAQS. The November 28, 2007 certification was determined to be complete on March 27, 2008 (73 FR 16205).