Abstract: Around 4:20 a.m. on January 24, 2020, Employee #1 had arrived at the worksite to begin work in the coating shop and sent a text message stating that he could smell and hear a propylene gas leak. The supervisor sent out a text to the crew stating "don't fire up the gun. Gas leak." A coworker responded "Call 911." Shortly after, an explosion occurred at or in the coating shop. Employee #1 and Employee #2 were killed in the explosion and fire. Propylene gas, used at the facility in the high velocity oxygen fuel coating process, was believed to have leaked, accumulating and finding an unknown source of ignition, resulting in the explosion. Two other employees, Employee #3 and Employee #4, were non-fatally injured by debris from the explosion.