Abstract: At 9:00 a.m. on October 26, 2019, an employee and an electrical contractor turned off the power to switch #1 of 5 in the main power supply disconnect located in the power distribution area of the production plant. The employees thought the switch controlled a hot circuit for the air dryer disconnect and disconnect switch located in the air compressor room. The employee checked the voltage across the three leads inside disconnect switch #1 with a voltage meter and it read zero for all of the leads. While the employee was unscrewing the third lead inside of disconnect switch #1, the wire popped out and hit the Allen wrench that he was using, resulting in an arc flash. The employee was hospitalized to treat first degree burns to both hands, second degree burns to his left forearm, and mild burns to his neck.