Abstract: At approximately 10:40 a.m. on January 21, 1993, Employee #1 was working on the third floor of a building under construction. A tool dropped from his pocket and fell down an air ventilation shaft. To retrieve the tool, he descended to the lowest level, which was two levels below ground surface. The shaft was open only at the third floor and in the ceiling of the lowest level. There the ceiling was 97 inches above the floor. The shaft was about 48 inches wide and 133 1/2 inches long in rectangular section. Although CAL/OSHA safety orders required two means of access to the third floor, only one such means of access was provided and it was in an unsafe location at a distance from the shaft. Employee #1, attempting to take a short cut back to his work post, stacked a number of buckets, mounted the stack, and proceeded up the shaft by pushing his hands against the shaft walls, stopping to rest on an occasional projection. He got within about 5 feet of the top of the shaft before falling all the way to the concrete floor, about 45 feet, and sustaining fractures in both legs. Paramedics transported him to a hospital.