Clean Air Act Approval and Promulgation of PMINF10 Implementation Plan for Denver, CO

EPA is approving the State Implementation Plan (SIP) revisions submitted by the Governor of Colorado for the purpose of bringing about the attainment of the national ambient air quality standards (NAAQS) for particulate matter with an aerodynamic diameter less than or equal to a nominal 10 micrometers (PM<INF>10) in the Denver area. The SIP revisions were submitted to satisfy certain Federal requirements for an approvable moderate nonattainment area PM<INF>10 SIP for Denver and, among other things, contain enforceable control measures. The bulk of the revisions were submitted on March 30, 1995. Revisions to Colorado Regulation No. 13 (oxygenated fuels), which is one of the control measures relied on in the SIP, were adopted by the Air Quality Control Commission (AQCC) on October 19, 1995 and submitted to EPA on December 22, 1995. EPA proposed to approve the March 30, 1995 submission on October 3, 1996. On December 6, 1996, EPA published a supplemental proposal to approve the Denver PM<INF>10 SIP based on the October 19, 1995 version of Regulation No. 13 rather than the prior version. This action supersedes EPA's July 25, 1994, final limited approval of certain control measures found in the State's June 7, 1993 Denver PM<INF>10 SIP submittal.