Abstract: At 7:45 a.m. on August 9, 2018, Employee #1 and a coworker, employed by an electrical services company, were working at the rehabilitation of a three-story commercial building, a multi-employer construction project. They were installing overhead electrical conduit in the building's mechanical room. Both employees were working on overhead ductwork at a height of 17 feet one inch from the top of the duct to the ground. They were using an extension ladder to access the ductwork. As the coworker performed work, Employee #1 assisted by getting tools, equipment, and other items for the task. From his position on top of the duct, Employee #1 attempted to descend the nearby extension ladder to obtain additional work materials. As he started to transition from the top of the duct to the ladder, he lost his balance and fell. He fell onto the mechanical unit and then continued falling, striking the concrete floor. Emergency services transported Employee #1 to the hospital, where he was admitted for treatment of multiple fractured ribs and a lumbar (lower spine) vertebral fracture.