1. Department of Occupational Health Engineering, Tabriz University of Medical Sciences, Iran
2. Department of Statistics and Epidemiology, Tabriz University of Medical Sciences, Iran
3. Health Management and Safety Promotion Research Institute, Tabriz University of Medical Sciences, Iran
4. Department of HSE, East Azerbaijan Province Gas Company, Iran
5. Department of Occupational Health Engineering, Faculty of Health, Tabriz University of Medical Sciences, Tabriz, Iran
6. HSE, Royal Dutch Shell, Netherlands