EPA inspected the facility on July 1, 2011. On October 18, 2013, EPA issued a Section 114 Information Request to Big River Resources Galva, LLC (Big River). The facility provided the requested information to EPA on December 5, 2013. The information obtained from Big River showed that the facility was not in compliance with conditions in its permit. On March 6, 2014, EPA issued Big River a Notice of Violation and Findings of Violation (NOV/FOV). The NOV/FOV alleged that at its TOs, Big River violated PM and acetaldehyde emission limits, failed to maintain the minimum combustion temperature operating requirement contained in its permit, and violated its NOx emission limit, as required by the New Source Performance Standard for Industrial-Commercial-Institutional Steam Generating Units at 40 C.F.R. Part 60, Subpart Db (Subpart Db). Upon receipt of the NOV/FOV, Big River initiated its compliance process by implementing a series of corrective actions related to the TOs. EPA held a Section 113 conference with Big River on April 22, 2014. At the meeting, and on April 18, 2014, April 25, 2014, and August 19, 2015, Big River provided additional information to EPA regarding the NOV/FOV allegations. Specifically, Big River demonstrated that the PM and acetaldehyde emission limits were established based on engineering design and approved industry typical standards. Since there was no mechanical way of improving or altering the equipment to meet the permitted limits, Big River sub