Abstract: Employees #1 and #2 were starting up the orchard heating system because of the cold weather. Employee #1 turned on the propane valve to the main line and noted the pressure, but no propane was in the tubing connecting the heaters. Employees #1 and #2 checked the tubing and about 4 minutes later returned to the main valve to try again. When they did this, a wall of flame enveloped both workers. They were able to get away quickly, but Employee #1 suffered burns to his face and hands, which healed without further problems. Employee #2 suffered burns to his hands, which required skin grafts on his right hand.