Abstract: At 1:30 p.m. on August 22, 2021, an employee working as an operations and maintenance technician for a bioscience research facility was troubleshooting an electrical system. The employee was investigating a power outage in Building B. The employee and a coworker, the facility supervisor, began troubleshooting the outage. The employee reset a switch in the outdoor substation, but the power did not return. The employee attempted to take a reading on one of the four lines that comes from the substation to an indoor 4160-Volt 6-Amp feeder. The feeder is located at Unit Substation 4 located in the penthouse of Building B. The employee opened a medium voltage transformer to access a switch located in the metal enclosed electrical cabinet to take a reading on the fuses when he caused an arc flash/blast. The employee was not wearing proper personal protective equipment, using proper electrical tools and had not received proper training in the high voltage electrical work. The employee was hospitalized to treat electrical shock and burns to his chest, arms, hands and fingers.