EPA is proposing to approve revisions to the South Coast Air Quality Management District (SCAQMD or District) portion of the California State Implementation Plan (SIP). These revisions concern the District's demonstration regarding Reasonably Available Control Technology (RACT) requirements for the 2008 8-hour ozone National Ambient Air Quality Standard (NAAQS) in the South Coast Air Basin and Coachella Valley ozone nonattainment areas. The EPA had previously proposed to partially approve and partially disapprove SCAQMD's RACT SIP demonstration. However, since publication of the proposed rule, SCAQMD has addressed the identified deficiency that was the basis for the proposed partial disapproval by completing additional analysis and by submitting the analysis to the EPA as a supplement to the RACT demonstration. Because the supplemental analysis adequately addresses the deficiency, the EPA is withdrawing the previous proposed action and is now proposing full approval of SCAQMD's RACT SIP demonstration for the 2008 ozone NAAQS, as recently supplemented. The action proposed herein is based on a public draft version of the SCAQMD RACT supplement, and the EPA will not take final action until submittal of the final version of the SCAQMD RACT supplement as a revision of the California SIP.