Abstract: At approximately 1:00 p.m. on March 10, 2011, an employer, a sole proprietor, and his employee were going to inspect and patch a low-slope (flat) roof on a one-story, existing commercial building. The employer and employee brought materials up to the roof to make repairs. The employer and employee cleared gravel from several locations on the roof. During this process, the employer determined that the damage was too extensive to repair and the roof needed to be replaced. No repair work was performed on the roof. The employer contacted the building owner to inform him of his assessment, and the building owner requested that the employer provide a cost estimate for replacement. The employer and the employee then measured the roof. During the final measurement, from west to east, the employer was walking backward. He tripped over the parapet wall, approximately eight inches wide and seven inches high, and fell to the ground. The employer sustained six broken ribs and a punctured lung. He was transported to Lutheran General Hospital, in Park Ridge, Illinois, for treatment and hospitalization. An emergency responder spoke with the employee who stated that he had informed the employer that he was "getting close to the roof edge and to be careful". The distance from the top of the parapet wall to the ground was approximately 18.6 feet. A witness loading a truck across the street stated that he saw the employer and employee on the roof, and when he turned back, he saw the employer on the ground. He then informed others to contact emergency response. The weather was windy and warm and not a contributing factor. The ground had recently thawed and was very soft.