Supplemental Brief of Petitioners and Petitioner-Intervenors, On Petitions for Review of Final Agency Action of the US EPA 80 Fed.Reg. 64,510 (October 23, 2015) and 81 Fed.Reg. 27,442 (May 6, 2016), In the United States Court of Appeals for the District of Columbia Circuit, No. 15-1381 (and consolidated cases)