The causes of scaffolding accidents resulting in employee casualties were analyzed. Whenever possible, the factor responsible for the initiation of the accident was identified as the primary cause, and the factor that could have mitigated the consequence of the accident was identified as the secondary cause. For any given accident there were often several causes, but only one primary cause. The accidents were classified as resulting from three major causes: systems failure, environmental factors, or human factors. Systems failures involved platforms, support elements, connections, anchorages, foundations, access ways, and safety devices. Systems failures occurred as a result of inadequate strength or lack of stability. Environmental failures were characterized by unexpected occurrences that threw employees off balance during work, exposure to toxic fumes, presence of an obstruction on the work platform, or insufficient warnings of physical hazards. Human factors were attributed to perceptual or behavioral failures. Of the 801 accidents examined, 8 percent involved the platform, 12 percent involved support elements, 21 percent involved connections, 13 percent involved anchorages, 10 percent involved foundations, and less than 1 percent involved access ways and safety devices. Environmental and human factors were the cause of 36 percent of the accidents. The authors conclude that in three out of four cases, the cause of scaffolding accident is attributable to systems failure.
NIOSH, U.S. Department of Health, Education and Welfare, Washington, D.C., 57 pages, 5 references