Visualization of a hole and accident preventive measures based on the Swiss cheese model developed by risk management and process approach

It is important to find the characteristics of holes theorized in the Swiss cheese model created by Reason when preventive measures are taken. Reason does not explain where the holes open and how the holes move and shut. The objectives of this research are to find the characteristics of a hole, visualize the development of the hole and propose accident preventive measures to shut the hole. I investigated four real cases of three types of marine accidents using risk management and process approach. The focus of the study was on the processes both of the Safety Management System and risk management imbedded in the procedures at the time of the accidents. I found the following results. A hole in a defensive layer opened during the process of plan or check imbedded in the Safety Management System and moved through the Plan-Do-Check-Act (PDCA) cycle. The hole in the defensive layer moved or affected the development of the hole in another defensive layer at the local workplace. The hole in another defensive layer at the local workplace opened during the process of risk identification or risk analysis and moved through risk management process. Shutting the hole was drawn in a structured manner by the method of risk reduction. With a focus on process, the development of holes was visualized. These findings indicate that the characteristics of holes and their visualization can show the location where efforts toward preventive measures should be directed effectively and efficiently.