Abstract: At approximately 1:30 p.m. on February 16, 2009, Employee #1, an air conditioning technician, and a coworker, his supervisor, were repairing an air conditioning unit. The air conditioning unit was repeatedly tripping the circuit breaker. The coworker removed the metal face plate from the main electrical panel to determine the voltage. The coworker reset the circuit breaker and confirmed the voltage output of 240 volts and an amperage draw of 13 to 15 amps per phase. The coworker instructed the employee to replace the metal face cover, while the coworker tended to the thermostats. The employee put on his protective face shield, picked up the metal face panel cover and squatted in front of the electrical panel. Before he could replace the cover, an electrical flash occurred from within the main electrical panel pushing him backwards, burning his face, hands, arms and legs, and activating the automatic fire suppression sprinklers. Employee #1 sustained second and third degree burns to his face, hands, arms and legs, and was hospitalized. The employee was wearing a long sleeve cotton work shirt and cotton work pants. An electrician hired to repair the damage caused by the accident determined that an electrical short circuit had occurred in the electrical conduit on the roof supplying the air conditioning unit. Leaves were found in the conduit and the fault was repaired.