A large explosion at a United States Steel Corp. plant in Pennsylvania on Monday morning left two people dead and 10 injured, U.S. media reported.The plant, located near Pittsburgh, is known as the largest coking operation in North America and is one of four major U.S. Steel plants in the state, according to The Associated Press.A senior U.S. Steel official said a single explosion had occurred and the cause was still unclear, CNN reported. Local authorities temporarily urged nearby residents to stay indoors.The blast occurred after Japanese steelmaker Nippon Steel Corp. completed its $14.1 …READ FULL ARTICLE