UNITED STATES COURT OF APPEALS FOR THE THIRD CIRCUIT _______________ No. 20-2215 _______________ CLEAN AIR COUNCIL, Appellant v. UNITED STATES STEEL CORPORATION _______________ On Appeal from the United States District Court for the Western District of Pennsylvania (D.C. No. 2:19-cv-01072) District Judge: Hon. Marilyn J. Horan _______________ Argued: January 29, 2021 Before: RESTREPO, BIBAS, and PORTER, Circuit Judges _______________ ORDER _______________ The panel has revised the opinion issued on June 21, 2021, and fixed a typographical error that appeared at page 16. The Clerk is directed to file the amended opinion. This amendment does not change the filing date. The judgment remains the same.

ATTEST: s/ Patricia S. Dodszuweit Clerk Dated: June 22, 2021 cc: All Counsel of Record