Abstract: At approximately 3:00 p.m. on August 21, 2012, an employee was working for ACCO Engineered Systems, Inc., an appliance repair and maintenance firm. The incident occurred in the business administration building of a university. ACCO Engineered Systems installed and serviced industrial ventilation systems. According to the employee, he had finished working on an air conditioning unit located on the roof of the building and was coming down by way of a fixed ladder. As he was closing the roof hatch with his right hand, he lost his grip on the ladder with his left hand. According to the employer's accident investigation report, the employee fell about 15 feet (4.6 meters) onto a concrete floor. The employee landed on his right side. He was working alone, and there were no witnesses. He managed to call emergency medical service using his cellphone. He was taken by paramedics to a trauma hospital. He sustained fractured ribs and a broken tibia and fibula. At approximately 5:22 p.m. that same day, the employer representative of ACCO Engineered Systems reported the incident.