Abstract: At about 1:00 p.m. on July 20, 1999, a supervisor assigned an apprentice electrician to vacuum and clean switchgear cubicles in a subbasement electrical room. The employee was to clean the cubicles of dust and metallic filings associated with recent terminations in the newly installed cubicles. The room contained four rows of four cubicles. The two outside rows were completely deenergized. The cubicles in the two inner rows were at least partially energized. The electric utility had padlocks on three of the 16 cubicles. Building management had padlocks on the remaining cubicles. The building manager unlocked the 13 the cubicles for which he had keys and walked the apprentice through the process, pointing out which cubicles needed to be cleaned. After cleaning the cubicle on the outside end unit of the left outer row, the apprentice began cleaning the cubicle on the outside end of the left inner row. (This cubicle was unlocked.) A 13.2-kilovolt underground feeder cable coming out of the floor though a vertical conduit supplied the cubicle. This cable was energized. At about 2:00 p.m., as he was using a dust rag to clean the inside of the cubicle, the apprentice apparently contacted the energized side of a 13.2-kilovolt knife switch with the dust rag and caused an electrical fault. The ensuing electric arc ignited his clothing. He sustained second- and third-degree burns to his face, arms, and torso. Emergency medical services transported the injured employee to a shock-trauma center, and he was transferred to a hospital 2 days later. He died of his injuries 8 days after the accident.