Abstract: Three Employees were repairing a hopper 50' above ground. Employee #1 was welding, Employee #2 was grinding and Employee #3 was the fire watch. Employee #1 was using a oxygen acetylene torch to cut the hopper. The torch hose was directly below the cutting operation, and as Employee #1 lit the torch, an explosion took place. Employee #1, Employee #2 and Employee #3 were burned and the Oxygen/Acetylene cylinders caught fire. Employee #1, Employee #2 and Employee #3, all sustained burns between 20-45 percent of their bodies,as well as respiratory burns. One employee will require skin grafts over 20 percent of their body.