A settling CAA defendant that violated PSD provisions at its integrated steel mini-mill in Peoria, Illinois, must pay a $565,000 civil penalty, install and use a sulfur dioxide (SO2) continuous emissions monitoring system, comply with specified SO2 emissions limits at its Arc Shop, make required modifications to each of its baghouse fan motors, develop for EPA approval a preventative maintenance and operation plan for all its emissions, and perform and complete a root-cause failure analysis for any extended duration heat.