Abstract: At 1:00 p.m. on August 5, 2003, Employee #1 was involved in an accident. Employee #1 started working on that day at 7:00 a.m. and his duties were repairing, servicing and installing air ducts. The rectangular 40-inches by 50-inch duct had been installed a few days before. On the day of accident, Employee #1 and a coworker came to the site to secure some sections of the air duct on the second floor. The second floor was already sheeted with plywood, except for a small hole adjacent to the air duct. While Employee #1 was securing the air duct on the side, he stepped into the small hole next to the air duct. Employee #1 fell into the hole, landed on the second floor joist, and fit so tightly into the hole that he could not pull himself out of the hole. There were no actual witnesses to the accident. Employee #1 was taken to Henry Mayo Hospital in Valencia for one hour. Employee #1 then drove back to the site from the hospital by himself. Employee #1 suffered minor lower back and neck pain from the fall.