Occupational accident patterns over five decades in a chemical plant: a case study focusing on the structural shift...

This study examines long-term occupational accident patterns in a chemical plant using approximately fifty years of internal incident records. These records were originally compiled for day-to-day safety management rather than for research purposes. They offer a rare retrospective view of how human-factor-related accidents and everyday safety practices actually evolved during long-term operation. Long-term trends in accident counts, frequency rates, and severity rates show a decline. However, closer examination indicates that as technical and equipment-related risks were reduced, incidents involving human judgment and action became relatively more prominent. In this sense, risk changed its form within the work environment. To explore this shift, incidents were examined using a cross-classification of "type of incident × unsafe behavior," together with a distinction between routine and non-routine operations. The analysis indicates that non-routine activities-such as maintenance and troubleshooting-remain particularly vulnerable to human-factor-related issues. When viewed through the lens of Hudson's safety culture maturity model, these patterns suggest a gradual transition from reactive to proactive practices. Rather than proposing a model of safety culture, this case study illustrates how long-term incident records reflect the practical, trial-and-error process of managing human factors and work. The findings offer insights for loss prevention and human-factor management.