In the factory, OSHMS (Occupational Safety and Health Management System) is often introduced to eliminate incidents and accidents in routine human work. In this system, the people who carry out production identify hazards that accompany daily activity in the factory, assess the risks involved in human work and, from the results of risk assessment, try to reduce these risks. Nevertheless, incidents and accidents continue to occur, one reason being oversight in hazard identification. This paper proposes a method to reduce the oversight of hazards during risk assessment in the plant. Based on a description of operational procedure by experienced production workers, the following three-step method is followed. 1) Experienced production workers identify potential hazards in the operational procedure based on their own knowledge; 2) by contextual analysis of the description, the production workers examine the possibility of incident or accident and identify hazards in the process from operation to incident or accident; and 3) hazards are identified from accidents and incidents occurring real operations or the imaginary incident envisaged by the production workers.