Abstract: On March 24, 2006, Employee #1 was installing aluminum window frames with two coworkers. They had preinstalled an aluminum channel into concrete of window opening at the head and at the sill and then they lifted preassembled aluminum frames into the channel by putting them into the head first and then bringing down to the sill. The dimension of window opening was 8.33 ft high and 14.5 ft wide. The ladder jack scaffold was used at the site and it consisted of two 10-ft, A-framed ladders and a scaffold plank. The ladder was manufactured by Green Bull and its model number was 204210. A 16 ft scaffold grade plank was used as platform, and it was positioned about 7 ft from the floor. Employee #1 was standing on the scaffold plank near one ladder, and coworker #1 was standing on the other side of window opening, while coworker #2 was operating the scissor lift to bring frame into the place for installation. Employee #1 became dizzy and passed out, falling off the scaffold to the concrete floor. He regained continuousness, when he landed on the floor and he had cut on the lip and gauche on the back of his head. The paramedics arrived and transported him to Los Angeles County USC Medical Center. Employee #1 sustained a fracture of his T-5 vertebrae and head laceration and was hospitalized for six days.