Explosions at a U.S. Steel plant that shook the ground near Pittsburgh left one dead and at least ten in hospitals Monday, with emergency workers still searching the badly charred rubble hours later for a missing worker, officials said. The explosions sent black smoke spiralling into the midday sky in the Mon Valley, a region of the state synonymous with steel for more than a century. Allegheny County Emergency Services said a fire at the plant started around 10:51 a.m. A search and rescue effort was still active on Monday afternoon and officials said they had not isolated the cause of the blasts. The explosions sent ... (full story)