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.

U.S. Steel last year settled a lawsuit brought by environmental groups over emissions that stemmed from the 2018 Clairton plant fire. The settlement with the groups and the county included $19.5 million in coke-oven upgrades and $17.5 million in other plant improvements.