According to Reuters, the blast at I Schumann & Co manufacturing plant in the city of Bedford, near Cleveland, created a towering pillar of smoke and brought fire engines racing from across the state.
Brian DiRocco, the fire chief for the nearby city of Oakwood, said most of the people hurt were “walking wounded” but that at least one was in critical condition.
Matthew Wiggins, a neighbouring business owner, told Ohio broadcaster WOIO that he heard a large explosion immediately followed by what sounded like “large amounts of debris” hitting his roof.
"Things were falling off the walls, falling off shelves. We went out front and there was like smoldering rocks and molten metal in the yard. Tons and tons of smoke. Fire billowing out of the building across the street," he said.
Another witness, Joe Sarconi, said he was eating lunch in his car across the street when he saw a metal beam “fly across the street”, saying it was “exciting, but horrible”.
Mr DiRocco said he had inspected the metals plant before and found it generally safe, except for the fact that it was a foundtry. “You are dealing with molten metal, so there's always an inherent danger,” he told reporters.