Hoosier is a non-profit generation and transmission cooperative providing electric power to 17 member electric distribution cooperatives in central and southern Indiana and one member cooperative in Illinois. Hoosier, headquartered in Bloomington, Indiana, owns and operates two coal-fired electric generating stations: Merom Generating Station (Merom), located in Sullivan County and Ratts Generating Station (Ratts), located in Pike County. The total gross coal-fired capacity is about 1,358 MW. These plants are subject to, among other things, Clean Air Act (Act) provisions regarding Prevention of Significant Deterioration (PSD), Non-attainment New Source Review (NNSR), and Title V.
On August 26, 2009, EPA Region 5 issued a notice of violation (NOV) to Hoosier for alleged NSR violations at Merom. The NOV alleged that in 2008, Hoosier made physical changes to the high temperature superheater outlet header, the radiant and high temperature superheater sections, and high temperature reheater tubes. The NOV also alleged that these physical changes resulted in a significant net emissions increase of regulated pollutants, including SO2, NOx, and/or PM. As such, these physical changes were major modifications within the meaning of the Clean Air Act and its implementing regulations, including 40 C.F.R. � 52.21 and the Indiana State Implementation Plan (SIP).
Shortly following receipt of the NOV, Hoosier requested a settlement conference to discuss resolution of the al