This article describes points of attention derived from conventional experiences about investigation methods of human error accidents in the industrial world. The following points are emphasized. First, a true cause of an accident cannot be grasped in accident investigations due to various disincentives. Second, we are not able to take effective measures accordingly. As a result, a cause of the accident is always referred to as "the cause easy to understand for everyone", "the cause from which a quick conclusion is obtained" and "the cause by which a countermeasure does not cost a lot of money". Therefore, in most cases, a cause is found to be a human error thus defined. And a measure may be recommended as a conclusion relying on human reorientation based on this etiology. Any accident investigation has to be performed from the following points of view based on this recognition. First, the investigation staff must be independent of all relevant organizations. Second, the investigation staff should have the strong authority. Third, the investigations have to be performed by using scientific methods. Fourth, an investigation staff member must consider organizational factors that do exist within a cause of the accident. At the end of the discussion, the "actual example" performed by an actual business establishment is introduced as a useful reference for other business establishments.
Accidents occur in every industry, incurring great loss of life and property. Therefore, accident prevention adjusted to particular types of accidents is an urgent issue. The objective of this study is to introduce the history and application of accident models in each industry and suggest effective accident prevention measures taking these models into account. Accident models are divided into major categories: sequential, epidemiological, and systemic. The accident model suited to each situation should be selected in accordance with the degree of tractability and coupling in the characteristics of each industry as well as the type of accident. Organizations must establish systematic accident prevention measures, which include scientific investigations and accident models that are applicable to the industry.