A study was conducted to design a comprehensive classification system for occupational accidents which would describe the array of causal factors, map their relative sequential relationships, evaluate the relative importance of factors in accident causation, and yet be operationally applicable. Information surrounding the occurrence of all traumatic work related fatalities in Australia in 1982 through 1984 was gathered. The coded information included factors immediately antecedent to the accident resulting in the fatality and factors removed in time which contributed to the occurrence of the accident. The complex network of events leading up to the accident, their interrelationships, and their relative contribution to causing the accident were examined. The results provided information about the use of accident analysis for the formulation of preventive strategies. Human error, poor work practices, and environmental factors were the most frequent antecedents of the fatalities. However, the prime causes of accidents were not necessarily those factors which were the most frequently involved. Error at some point in the sequence was the most frequently involved factor, and was also the most common prime causal factor. Environmental factors were prime causal factors in only a minority of cases. The authors conclude that these results clearly demonstrate that the nature and influence of events occurring earlier in the sequence has important implications for drawing inferences about preventive strategies.