Authorities said their investigation has shifted to the cause of the explosion after they accounted for everyone who was missing.

An investigation is underway to determine what caused a massive blast at the U.S. Steel plant in Clairton, Pennsylvania, that left two people dead and at least 10 injured. Authorities say the factory is now stable and secure but the full extent of the damage is unknown and are encouraging everyone within one mile of the plant to stay indoors and keep their doors and windows closed.

At least one person has died, and one person remains unaccounted for, while at least 10 people have been injured following multiple explosions at the U.S. Steel Clairton plant.