Abstract: On January 29, 1993, Employees #1 through #4 were recompleting a well and had started tripping stands of pipes that morning. After the fourth stand was installed, the operator told the floor hand to put the pump in second gear. The floor hand performed the task successfully. The floor hand proceeded to the well and noticed fluid flowing over the BOP. The operator told the floor hand to shut the hydril. When the floor hand returned to the well, he was met by the operator. Both of them immediately went back to the accumulator to see if the hydril was closed. The hydril was in the closed position. Meanwhile an accumulation of hydrocarbons escaped the well and filled the cellar. When the operator and the floor hand returned to the well, they were immediately hit with a fireball of flames that had originated from the back of the workover rig. The operator and two floor hands sustained severe burns to their faces and various parts of their bodies. The derrickman sustained minor burns to his face. There were no fatalities. There was no known source of ignition.