EPA is taking final action to find that Arizona failed to make a state implementation plan (SIP) submittal required under the Clean Air Act (CAA or Act) for the Maricopa County (Phoenix) nonattainment area (Maricopa area) for particulate matter of 10 microns or less (PM- 10). The Maricopa area is a serious PM-10 nonattainment area which, having failed to attain the PM-10 National Ambient Air Quality Standards (NAAQS) by its required statutory attainment deadline, is subject to section 189(d) of the CAA. For such areas, section 189(d) requires that states submit within 12 months after the applicable attainment date, plan revisions which provide for attainment of the PM- 10 NAAQS, and from the date of such submission until attainment, for an annual reduction of PM-10 or PM-10 precursor emissions within the area of not less than 5 percent of the amount of such emissions as reported in the most recent inventory prepared for the area. Arizona submitted a section 189(d) plan for the Maricopa area on December 21, 2007, and EPA proposed action on this plan on September 9, 2010. On January 25, 2011, prior to final action on the plan by EPA, Arizona withdrew the submitted plan from the Agency's consideration. As a result of the withdrawal, EPA is today finding that Arizona failed to make the submittal required for the Maricopa area under section 189(d) of the Act. This action triggers the 18-month clock for mandatory application of sanctions and 2-year clock for a federal implementation plan (FIP) under the Act. This action is consistent with the CAA mechanism for assuring SIP submissions.