Abstract: At approximately 8:20 p.m. on March 5, 2012, Employee #1 an assistant plant operator, was backing a 4160 breaker back in when the breaker exploded causing a fire. Employee #2 was in the area to assist Employee #1 and when the explosion occurred, he called for assistance from the plant. Someone in the plant called 911 and Employee #1 was transported to Palmetto Richland Memorial Hospital with second degree burns. Employee #1 was eventually transferred to the Augusta Burn Center. Employee #2 was treated and released for smoke inhalation. Employee #1 has had extensive training in his job as an APO and is required to go through a 9 step APO training program. He was wearing a 40 cal Arc Gear which included coveralls, gloves, and an electric arc flash hood. Employee #1 was wearing the proper personal protective equipment and had also received training in lockout tagout.