Abstract: At approximately 9:00 a.m. on October 7, 1998, Employee #1 was working on the roof of a scale house. He was rising from a kneeling position when he stepped onto an unsupported section of plywood, and fell 13 1/2 ft through the roof onto a concrete slab. Employee #1 suffered a fractured right hip and lacerations and abrasions to his right arm. The primary cause of the accident was Employee #1's lapse of memory so that he stepped on the unsupported plywood. A secondary cause, which also contributed to the severity of the injuries, was the employer's failure to provide and to insist on the use of effective fall protection. Employee #1 had 11 years of experience as a heavy equipment operator; he had been working as a carpenter for two months,.