Abstract: At 1:00 p.m. on February 24, 2017, an employee was working for a drywall and insulation contractor. He was working in a three-story building. From 7:00 a.m. until 10:00 a.m., he helped build and erect new exterior walls on the third floor. Then he cleaned up debris on the second floor. At that point, he recognized that he had left his tool belt on the third floor. He climbed a ladder to the third floor to retrieve his tool belt and hammer. As he walked close to a wall opening to retrieve his tools, he slipped on a piece of debris. He lost his balance and fell through an unguarded wall opening of 3.4 meters by 2.4 meters (11 feet by 8 feet). He fell 5.9 meters (19 feet, 6 inches) onto a retaining wall comprised of compacted soil. He was not wearing fall protection. According to an interview with the employee, he fractured a rib and sustained bruises to his back, side, and arm. He was hospitalized.