Abstract: At approximately 11:00 a.m. on May 18, 2005, Employee #1 was working inside an electrical vault (M-7814). He was trying to spike an insulated conductor before cutting it to make sure that it was de-energized and grounded. He used a hot stick to install the spiking tool on the conductor while standing on a ladder inside the vault. Feeling that the spiking tool's pin was not sharp enough to penetrate the insulation, he realized that he needed more torque on the hot stick. Employee #1 asked his coworker for a flathead screwdriver. As he later recalled, he was trying to tighten the spiking pin with the screwdriver when an explosion occurred. He heard the explosion, saw a flash of white light, and felt heat before he was knocked down to the floor. After about a minute he began to climb the ladder but collapsed onto the ground. Employee #1 sustained flash burns to his face, ears, and neck, for which he was hospitalized.