Approval and Promulgation of Air Quality Implementation Plans; Designation of Areas for Air Quality Planning Purposes; Arizona; San Manuel Sulfur Dioxide State Implementation Plan and Request for Redesignation to Attainment

EPA is taking direct final action under the Clean Air Act to approve the Final State Implementation Plan Revision, San Manuel Sulfur Dioxide Nonattainment Area, March 2007 as a revision to the Arizona state implementation plan. The Arizona Department of Environmental Quality developed this plan to maintain the sulfur dioxide national ambient air quality standards in the San Manuel, Arizona area and to request redesignation of the area to attainment. The maintenance plan contains various elements, including contingency provisions that will be implemented if measured ambient concentrations of sulfur dioxide are above certain trigger levels. EPA is also approving the State of Arizona's request for redesignation of the San Manuel area from nonattainment to attainment for the sulfur dioxide standards. EPA is taking these actions consistent with provisions in the Clean Air Act that obligate the Agency to approve or disapprove submittals of revisions to state implementation plans and requests for redesignation. The intended effect is to redesignate the San Manuel, Arizona sulfur dioxide nonattainment area to attainment, and to provide for maintenance of the standard for the ten-year period following redesignation.