Document vVndBr4xZV2VdQKypXRqmpm08

USCA Case #24-1287 Document #2077531 Filed: 09/30/2024 Page 10 of 81 The Data EPA Used Were Insufficient to Calculate the MACT Floor Limits. 25. Even based on its limited dataset, EPA's conclusion that SunCoke's facilities can meet the new numerical MACT floor emissions limits without any additional controls is unsupportable. To draw this conclusion, EPA had to assume that all SunCoke's facilities with a main stack, for example, could satisfy the new MACT floor limit for mercury merely because one of SunCoke's facilities (IHO) met the Emit (though not by much). EPA's assumption is baseless. As discussed, SunCoke has data showing that HH1's main stack failed to meet the MACT floor Emit for mercury emissions. That is not surprising. Different SunCoke facilities are equipped with different controls and therefore perform differently. So EPA was wrong to assume that all of SunCoke's facilities' main stacks could perform as well 1HO's main stack. 26. EPA also did not consider other important factors that can alter how a facility performs on a given day, such as the naturally occurring variability of the coal that SunCoke puts into its ovens. The coal that SunCoke purchases has variable concentrations of different chemicals, including mercury. Change in the coal mercury levels will change the amount of mercury emissions at a plant like HH1, which is (Page 10 of Total) - 10- Sierra Club FOIA 2025-EPA-04883 ED_018388_00000109-00109 SC_EVERSPLIT0005783