Abstract: During the weekly check of the sump pumps on the wharf, Employee #1 arrived at berth #9, where the pump was running continuously. He called his coordinator, who stated it appeared that the float was stuck. To free it, Employee #1 would have to lift the cover and see. As he lifted the cover, it slipped from his hands and fell on the wires to the motor and controls, causing an electrical flash. An unknown vapor within the sump pit was detonated and exited upward through the now open cover slot, striking Employee #1 in the face, neck, and chest and igniting his Nomex coveralls. Employee #1 jumped from the wharf to the water and extinguished the flame. He climbed the ladder back to the wharf, where fellow workers assisted him. He was taken to the plant infirmary and later transferred to Brookside Hospital in San Pablo, where he was diagnosed as suffering first- and second-degree burns.