Preparations for a routine maintenance task may have led to an explosion at a U.S. Steel coal-processing plant near Pittsburgh that left two dead and sent 10 to hospitals, the company said Friday. U.S.

Timothy Quinn, 39, of East Huntingdon Township, also died in the incident. Ten other people were injured. Three of them are still hospitalized.

Ten people were hospitalized after the blast at a coke plant in Clairton, Pa., near Pittsburgh. One person who had been missing was found dead late on Monday.

A gas valve failure during maintenance work may have led to the fatal explosion at the U.S. Steel Clairton plant in Pennsylvania.