Two workers died and at least 10 people were injured after multiple explosions at the U.S. Steel Clairton plant.

U.S. Steel says it believes a gas valve failure led to the explosion Monday morning at its Clairton Coke Works, in which two workers died and 10 others were injured.

Rescuers were continuing to search for one missing worker at the Clairton Coke Works more than five hours after mid-morning explosions rocked the Mon Valley plant. The blasts killed one person and injured 10.