Abstract: At approximately 7:00 p.m. on December 12, 2007, Employee #1, a journeyman-laborer working on the 29th floor of a building in San Francisco, climbed-up a column form to pour concrete. He had his positioning hook tied and connected onto a vertical bar on top of the column. Employee #1 was standing on a clamp of the column's plywood form box and was pouring concrete into the column form by operating the nozzle of the concrete pumper. As he was working, Employee #1's weight caused the rebar to bend. His positioning hook suddenly slipped off the rebar projection and he fell approximately 6 ft backward onto the concrete flooring. Employee #1 fractured his twelfth thoracic vertebra (T12); he was transported to St. Luke's Hospital, where he was treated for several days. Subsequent investigation determined that the accident resulted from a violation of T8CCR 1637(a) Scaffolds--General Requirements: Employees pouring concrete into column forms should be standing on a solid construction at least 20 in. wide, rather than on a clamps box. In addition, it was determined that the employer failed to provide other safe options for employees to stand on during pours, such as a ladder or a scissor lift.