Air Plan Approval; Indiana; Temporary Alternate Opacity Limits for American Electric Power, Rockport

The Environmental Protection Agency (EPA) is proposing to approve a revision to the Indiana State Implementation Plan (SIP), authorizing temporary alternate opacity limits (TAOLs) at the American Electric Power, Rockport (AEP Rockport) facility during periods of unit startup and shutdown. This action is consistent with the Clean Air Act (CAA) and EPA policy regarding emissions during periods of startup and shutdown. Indiana has provided an air quality analysis demonstrating that this revision will continue to protect the applicable National Ambient Air Quality Standards (NAAQS) for fine particulate matter (PM 2.5 ) in Spencer County.