NEW YORK— ATI Allegheny Ludlum Corp. and North American Stainless Inc. (NAS) are challenging in the U.S. Court of Appeals a ruling by the U.S. Court of International Trade (CIT) allowing the removal of anti-dumping duties on stainless steel sheet and strip from Mexico. The issue dates back to 2011, when AK Steel Corp., ATI and NAS challenged a U.S. International Trade Commission (ITC) ruling that effectively removed dumping duties on shipments from Mexico (amm.com, Sept. 2, 2011). The CIT in November rejected the arguments by the U.S. producers and dismissed the case (amm.com, Nov. 16).