Abbas Soleimani - M.Sc. of HSE, Science and Arts University, Yazd, Iran
Gholamhossein Halvani - Assistant Professor, Department of Occupational Health Engineering, School of Public Health, ShahidSadoughi University of Medical Sciences, Yazd, Iran
Mehdi Jafari Nodoushan - M.Sc. of Occupational Health, Department of Occupational Health Engineering, School of Public Health,Shahid Sadoughi University of Medical Sciences, Yazd, Iran

Every year, many people in the world lose their lives due to occupational accidents and suffer many times more disabilities and injuries, and the direct cost of these accidents in the world is amount to billions dollars. Among the causes of accidents, the human error and unsafe behavior are known as the most important factors. Studies showed that biorhythms affect human errors and occupational accidents. This study aimed to investigate the relationship between biorhythms and severity of occupational accidents in a chemical industry. In this study, chemical industry accidents from ۲۰۰۹-۲۰۲۲ (۱۳ years) were investigated. The investigated accidents were classified into two groups of major and minor. Information related to the biorhythms cycles was analyzed using Natural Biorhythm software. Data analysis was done in SPSS-۲۴. The investigation of accidents showed that ۱۱۵ people involved in major accidents and ۱۶۴ people involved in minor accidents. In this study, in the critical state of the intellectual cycle, the number of major accidents was significantly higher than minor accidents (P=۰.۰۰۹). In the investigation of morning shift work accidents, the relationship between the critical state of the intellectual cycle and the severity of accidents was confirmed (P=۰.۰۰۴). We found no significant relationship between physical and emotional cycles with the severity of accidents. The results of the present study showed that the critical days of the intellectual biorhythm are related to the severity of occupational accidents.

Occupational accidents, Accidents severity, Biorhythms, Chemical industry