Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality Planning Purposes; Indiana; Lake County Sulfur Dioxide Regulations, Redesignation and Maintenance Plan

EPA is approving a State Implementation Plan (SIP) revision for the control of sulfur dioxide (SO<INF>2</INF>) emissions in Lake County, Indiana. The SIP revision submitted by the Indiana Department of Environmental Management (IDEM) amends 326 Indiana Administrative Code (IAC) Article 7. Indiana's revised SO<INF>2</INF> rule consists of changes to 326 IAC 7-4 which sets forth facility-specific SO<INF>2</INF> emission limitations and recordkeeping requirements for Lake County. The rule revision also reflects updates to company names, updates to emission limits currently in permits, deletion of facilities that are already covered by natural gas limits, and other corrections and updates. Due to changes in section numbers, references to citations in other parts of the rule have also been updated. EPA is also approving a request to redesignate the Lake County nonattainment area to attainment of the SO<INF>2</INF> National Ambient Air Quality Standards (NAAQS). In conjunction with these actions, EPA is also approving the maintenance plan for the Lake County nonattainment area to ensure that attainment of the NAAQS will be maintained. The SIP revision, redesignation request and maintenance plan are approvable because they satisfy the requirements of the Clean Air Act (Act).