Workers were heating coal and preparing for routine maintenance when an explosion rocked a U.S. Steel plant outside Pittsburgh

“It is with profound sadness that I share with you that the U. S. Steel colleague who had been unaccounted for has been located and confirmed deceased, following an extensive search and rescue effort," David Burritt, the company's CEO, said in a statement. At least 10 people were injured in the blast, officials said.

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.

An explosion at a U.S. Steel plant near Pittsburgh left one dead and dozens injured or trapped under the rubble Monday, with emergency workers on site trying to rescue victims, officials said. The explosion sent black smoke spiralling into the midday sky in the Monongahela Valley,

Emergency responders are working to free people trapped under rubble at the Allegheny County plant, the Associated Press has reported.