Abstract: Two septic maintenance workers were pumping out a 9475-liter (2500-gallon) underground septic tank. They were sitting on the upper part of a concrete manhole located inside an enclosure containing three 25-kilovolt (14.4-kilovolt, phase-to-ground) transformers. The enclosure was intended to permit access only by qualified persons, and the energized parts on the backs of the transformers were only 0.9 meters (3 feet) from the manhole. One of the two employees was using a hand-held metal tool with a 1.9-meter-long (6.2-foot-long) metal handle to break up the solid contents of the tank. The other employee was holding onto a 76-millimeter-diameter (3-inch-diameter) rubber suction hose that had been placed in the tank. As the first employee was removing the metal tool from the septic tank, the handle of the tool contacted the energized parts on the center transformer and caused an electrical fault. This employee received an electric shock and sustained third-degree burns on both hands and second-degree burns behind both legs and on his right buttock. The other employee was also burned by the ensuing electric arc. He sustained third-degree burns on the backside of his right leg and first- and second-degree burns elsewhere. The employees were hospitalized for their injuries. Neither employee was qualified to enter the transformer enclosure.