Abstract: On April 27, 1992, Employee #1 was operating a circulating pump at the ARCO Youlumme Oil Lease, well #87-11, in Maricopa, CA. KCL water was being circulated around the packer in the well to a 500 barrel recovery tank about 10 ft from the pump. After water circulated about 20 minutes, combustible gases began coming into the open top recovery tank from the oil well. The pump was throttled back to reduce flow, but gases continued coming into the tank. The gases drifted out of the tank over to the pump, causing the pump engine to race and an explosion to occur simultaneously. Employee #1 heard the pump engine race and explode. Then he saw the fire and ran. Employee #1 was taken by helicopter to Kern Medical Center, Bakersfield, CA. He was later transferred to Fresno Burn Center for treatment of second-degree burns to his face and back and third-degree burns to his arms. Employee #1 remained in the hospital until June 10, 1992.