A welder was pre-heating the boom of a PC 3000 shovel machine with a tiger torch, prior to completing some welding work. The welder didn't identify that there was a propane leak coming from a connection fitting on the torch's valve. The welder continued to pre-heat the boom with the leaking torch until the propane leak became substantial enough to ignite, which caused a flash that engulfed the welder.

The worker's PPE helped reduce the hazardous contact of the flames. The welder immediately shut off the propane supply and the supervisor took the welder to first aid for treatment of 1st and 2nd degree burns to her face.

During the preliminary investigation, it was determined that the fitting that feeds the torch with propane had a crack in it. This caused propane to leak out and settle in a pocket until it ignited.

(See attached pdf for more details and images)