Abstract: At approximately 10:00 a.m. on January 21, 1997, Employee #1, who worked for a heating and air conditioning company, was repairing a furnace inside a single-story residence. He used a 24 ft extension ladder that he placed on the north side of the building to check the flue on the roof. The ladder was extended 3 ft past the roof edge. Employee #1 climbed the ladder and placed his left foot on the roof to see if it felt safe. Employee #1 always kept his right foot on the ladder until his left foot felt secure. This time his left foot was on an old, wet wood shingle roof that also had moss growing on it, and Employee #1 slipped and fell 9 ft 10 in. to the ground. He landed on his buttocks and sustained a second lumbar vertebra fracture. He was taken to Sierra View Hospital for x-rays and was then released. Employee #1 had worked for this company for more than twelve years. He had been well trained, and the company had regular tail gate meetings. The ladder was inspected and found to be well maintained. No violations were found with respect to this accident.