Abstract: At 4:45 pm on April 28, 2011 an employee fell off the truck approximately 4 to 5 feet down landed on the ground. This accident was reported by the employer. On May 6, 2011, the accident occurred at the job site located at 636 El Camino Real, South San Francisco CA. During the course of this investigation, It was determined that on April 28, 2011, approximately 4:45 PM, an employee # 1 climbed up on a parked 'Concrete Pump Truck' Schwing 1993 , 36 meter pump) to assist employee #2 who was cleaning the pump. The employee #1 stated as he was walking on the side platform of this truck, his knee buckled and he lost his balance which caused him fall approximately 70 inches below on the ground. As a result of this accident, employee fractured his Pelvic and hospitalized for more than 24 hours. The employee #2 stated that he did not witness this accident directly, however he responded to the employee # 1 after the accident. The employee #1 stated that he was the foreman and trained for this job. There was no tripping or slipping hazard on the platform at that time. It was just his knee which caused this injury. Comments: There was no violation found at this time.