An explosion at a U.S. Steel plant south of Pittsburgh killed two people and injured more than 10 others. The CEO has vowed to find out what caused Monday's blast while the workers' union says it will make sure there's a thorough investigation.

A devoted dad has been identified as one of the two steel workers killed from an explosion at a Pennsylvania steel plant on Monday, officials said.

“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.