EPA is finalizing its determination that the Dallas/Fort Worth (DFW) moderate 8-hour ozone nonattainment area failed to attain the 1997 8-hour ozone national ambient air quality standard (NAAQS or standard) by June 15, 2010, the attainment deadline set forth in the Clean Air Act (CAA or Act) and Code of Federal Regulations (CFR) for moderate nonattainment areas. This final determination is based on EPA's review of complete, quality assured and certified ambient air quality monitoring data for the 2007-2009 monitoring period that are available in the EPA Air Quality System (AQS) database. As a result of this final action, the DFW area will be reclassified by operation of law as a serious ozone nonattainment area for the 1997 8-hour ozone standard on the effective date of this rulemaking. The new attainment date for the DFW area is as expeditiously as practicable, but not later than June 15, 2013. The State of Texas must submit State Implementation Plan (SIP) revisions addressing requirements for "serious" areas no later than one year after the effective date of this rulemaking.