The primary activity at Respondent’s facility is the processing of com to manufacture starch derivatives. On or about March 5-7,2013, EPA conducted an inspection of Respondent’s facility to determine compliance with Section 112(r) of the CAA and 40 C.F.R. Part 68. Records collected during the inspection showed that Respondent has exceeded the threshold quantity for propylene oxide, storing a maximum of approximately 57,275 pounds. Propylene oxide is a regulated substance pursuant to 40 C.F.R. § 68.3. The threshold quantity for propylene oxide, as listed in 40 C.F .R. § 68.130, Table 1, is 10,000 pounds. Company failed to: