The U.S. Chamber filed an amicus brief urging the D.C. Circuit to hold that a letter issued by the Environmental Protection Agency, which reversed statutory interpretations that EPA had definitively announced three months earlier, is a judicially reviewable final agency action, and inconsistent with Section 328 of the Clean Air Act. Thomas A. Lorenzen, Elizabeth B. Dawson, and Siyi Shen of Crowell & Moring LLP and the U.S. Chamber’s Litigation Center served as co-counsel for the U.S. Chamber.