Abstract: At 10:01 a.m. on May 31, 2019, Employees #1, #2, and #3, employed by an electrical contractor, were dismantling and removing electrically powered yard dying equipment from a closing factory. To remove large gauge copper electrical wiring from an electrical panel, Employee #1, the supervisor, used a hand-held battery powered grinder with a cutting wheel installed. The covers had been removed and the power had not been disconnected/secured. During the cutting, live electrical wires containing different phases of power came into contact with each other and created a phased electrical arc flash and explosion. The employees were transported to the hospital for treatment of electrical burns. Employee #1, who received the bulk of the arc flash, was hospitalized for treatment of severe burns to his upper body and arms. Employees #2 and #3 sustained minor to moderate burn injuries. They were treated and released without hospitalization.