Approval and Promulgation of Air Quality Implementation Plans; Indiana; Lead (Pb) Maintenance Plan Update for Marion County

EPA is approving a request submitted by the Indiana Department of Environmental Management (IDEM) on April 1, 2009, to revise the Indiana State Implementation Plan (SIP) for lead (Pb). The State has submitted an update to its Pb maintenance plan for Marion County for continued attainment of the 1.5 micrograms per cubic meter ([mu]g/m\3\) National Ambient Air Quality Standard (NAAQS) promulgated in 1978. This update satisfies section 175A of the Clean Air Act (CAA), and is in accordance with EPA's May 10, 2000, approval of the State's Redesignation Request and Maintenance Plan for the Marion County Pb nonattainment areas. Additionally, this Pb maintenance plan satisfies the requirements for maintenance plans contained in the September 4, 1992, EPA memorandum entitled "Procedures for Processing Requests to Redesignate Areas to Attainment."