Approval and Promulgation of Air Quality Implementation Plan; Missouri; Final Disapproval of Interstate Transport State Implementation Plan Revision for the 2006 24-Hour PM2.5 NAAQS

Pursuant to our authority under the Clean Air Act (CAA or Act), the Environmental Protection Agency (EPA) is taking final action to disapprove the portion of the "Infrastructure" State Implementation Plan (SIP) (CAA section 110(a)(1) and (2)) submittal from the State of Missouri intended to address the CAA section relating to the "interstate transport" requirements for the 2006 24-hour fine particle (PM<INF>2.5</INF>) National Ambient Air Quality Standards (NAAQS) that prohibit a state from significantly contributing to nonattainment or interfering with maintenance of the NAAQS in any other state. This final action to disapprove the "interstate transport" portion of the Missouri SIP submittal received by EPA on December 28, 2009, only relates to those provisions and does not address the other portions of Missouri's December 28, 2009, submission. The rationale for this action and additional detail on this disapproval were described in EPA's proposed rulemaking published in the Federal Register on March 18, 2011. The effect of this action will be the promulgation of a Federal Implementation Plan (FIP) for Missouri no later than two years from the date of disapproval. EPA's proposed Transport Rule, when final, is the FIP that EPA intends to implement for Missouri.