Subject: Revised Sulfur Dioxide MACT Floor, Data Variability Analysis, and Emission Limit for New Large HMIWI

response to the remand of the new source performance standards (NSPS) and emission guidelines (EG) for hospital/medical/infectious waste incinerators (HMIWI) by the U.S. Court of Appeals for the District of Columbia Circuit (the Court) and satisfied the Clean Air Act (CAA) Section 129(a)(5) requirement to conduct a review of the standards every 5 years. The promulgated rule revised the NSPS and EG emission limits for all nine of the CAA Section 129 pollutants--— particulate matter, lead, cadmium, mercury, chlorinated dibenzo-p-dioxins/dibenzofurans, carbon monoxide, nitrogen oxides (NOX), hydrogen chloride, and sulfur dioxide (SO2). Emission limits were revised for all three HMIWI size subcategories (large, medium, and small) for the NSPS and all four HMIWI size subcategories (large, medium, small, and small rural) for the EG. Following promulgation of the revised emission limits, an industry representative informed EPA of an error in the published NSPS emission limit for NOX for new large HMIWI, which did not appear to reflect EPA’s described analytical process for adopting the revised standards.1 On review, EPA staff determined that the published revised NOX NSPS for new large HMIWI indeed did not reflect EPA’s intent in the final rule. Prior to promulgation, the NOX emission limit for new large HMIWI was tentatively estimated to be 150 parts per million by volume, dry basi