Abstract: At 10:30 a.m. on June 29, 2012, Employee #1 was walking backwards unrolling a cap sheet (top ply of a built-up roofing membrane) while a coworker bent down holding the roll. Employee #1 fell through the unguarded skylight opening when he tripped backwards over the skylight curb. Employee #1 landed on the concrete floor below, a fall height of approximately 21 feet and four inches. The skylight opening was eight feet long and four feet wide. Employee #1 was taken by ambulance to San Francisco General Hospital's Emergency Department for evaluation and treatment of his injuries. Employee #1's leg was splinted and the laceration to the bridge of his nose was sutured. Employee #1 was admitted for further observation at the trauma unit and was discharged the next day at 5:00 p.m. On July 16, 2012, Employee #1 was admitted at San Francisco General Hospital, where he underwent surgery on his fractured left heel, described as "open reduction internal fixation of the left calcaneus fracture" in the medical report. Employee #1 was discharged from the hospital on July 19, 2012.