Republic Engineered Products (REP) exceeded twenty percent opacity as a three-minute average for visible particulate emissions of fugitive dust from its Basic Oxygen Process (BOP) vessels L and N on several occasions between 2003 and 2007. REP also exceeded twenty percent opacity as a six-minute average for visible particulate emissions of fugitive dust from its blast furnace casthouse #4. Evidence of the violations consists of REP'S own required weekly visible emissions observations performed and recorded on the roof monitor for the BOP vessels L and N, as well visible emissions observations conducted by U.S. EPA and Ohio EPA. Since 2003, REP has undertaken a number of repair and replacmenet projects on the capture and control systems for the BOP vessels, costing $18,932,564, to comply with the Ohio SIP and Title V permit requirements. The ACO requires REP to demonstrate and maintain compliance with Ohio SIP and Title V permit visible particulate emission limitations, as well as complete additional projects to enhance the secondary control and capture system for BOP vessels L and N.