Approval and Promulgation of Air Quality Implementation Plans; Massachusetts; State Implementation Plan Revision To Implement the Clean Air Interstate Rule

EPA is approving a State Implementation Plan (SIP) revision submitted by the State of Massachusetts on March 30, 2007. This revision addresses the requirements of EPA's Clean Air Interstate Rule (CAIR), promulgated on May 12, 2005 and subsequently revised on April 28, 2006 and December 13, 2006. EPA has determined that the SIP revision fully implements the CAIR requirements for Massachusetts. Therefore, as a consequence of the SIP approval, the Administrator of EPA will also, in a separate document, issue a final rule to withdraw the Federal Implementation Plan (FIP) concerning NO<INF>X</INF> ozone- season emissions for Massachusetts. In the SIP revision that EPA is approving, Massachusetts will meet CAIR requirements by participating in the EPA-administered cap-and- trade program addressing NO<INF>X</INF> ozone-season emissions. Massachusetts's SIP revision is based on EPA's model CAIR NO<INF>X</INF> ozone season rule and is, in most respects, substantively identical to that model rule. The Massachusetts CAIR program has two major substantive differences from that model rule (expanded applicability, and a different methodology for allocating NO<INF>X</INF> allowances), both of which are consistent with the flexibility allowed under CAIR for state participation in the EPA- administered cap-and-trade program. The SIP revision complies with the statutory and regulatory requirements for approval of a CAIR NO<INF>X</INF> ozone-season program. This action is being taken in accordance with the Clean Air Act.