Human factors in large-scale technological systems' accidents: Three Mile Island, Bhopal, Chernobyl

Many serious large-scale technological systems' accidents, having grave conse quences, such as those of Three Mile Island, Bhopal and Chernobyl, have pri marily been attributed to "operator error." However, further investigation has revealed that a large majority of these incidents are caused by a combination of many factors whose roots can be found in the lack of human factors (micro- and macro-ergonomics) considerations. Relevant human factor considera tions, the causes of human error, and commonalities of human factor problems in major disasters are briefly reviewed. We concluded that system accidents are caused by the way the (system) parts — engineered and human — fit together and interact. Also, on many occasions, the error and the resultant failures are both the attribute and effect of such factors as complicated operational pro cesses, ineffective training, non-responsive managerial systems, non-adaptive organizational designs, haphazard response systems, and sudden environmen tal disturbances, rather than being their cause. Recommendations for preven tion of such accidents are provided.