Abstract: At 2:00 a.m. on July 14, 1991, Employee #1, a dry and grind operator, was manually resetting the mill equipment system which had shut down automatically due to a raw material overload. Gypsum dust covered the aisles, stairways, and mill equipment, including the electrical system. Employee #1 slipped on the gypsum dust and fell from the 14th step of a 15-step metal stairway in the southwest area of the mill. He sustained multiple injuries and was killed. The stairway had 8 in. risers, a 2 ft 6 in. inside width, and a 2 ft. 11 in. outside width. Employee #1 had worked at the plant since October 5, 1978.