Tehran University of Medical Sciences Journal of Air Pollution and Health 2476-3071 6 3 2022 01 01 225 232 Ali Poormohammadi Center of Excellence for Occupational Health, Research Center for Health Sciences, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran Effat Sadat Mir Moeini Center of Excellence for Occupational Health, Research Center for Health Sciences, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran. Mohammad Javad Assari Research Center for Health Sciences, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran Salman Khazaei Research Center for Health Sciences, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran Saed Bashirian Research Center for Health Sciences, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran Mohsen Abdulahi Malayer Health Center, Hamadan University of Medical Sciences, Hamadan Iran Ghasem Azarian Research Center for Health Sciences, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran Fereshteh Mehri Nutrition Health Research Center, Hamadan University of Medical Sciences, Hamadan, Iran 2021 11 10 2021 12 18 Introduction: Azandarian industrial zone with about 40 active silica crushing units is one of the largest industrial area in Hamadan province, Iran. Materials and methods: In this study, the personal exposure of workers in the activated silica crushing units was measured. Assessing the risk of mortality due to exposure to Respirable Crystalline Silica (RCS) in the workplace was then estimated through measuring the personnel exposure in accordance with the National Institute for Occupational Safety and Health (NIOSH) 7601 method. Moreover, the mortality rate of lung cancer and risk of mortality due to exposure to RCS were estimated. Results: Based on the results, the average exposure of employees to RCS in the crushing units was in the range of 1.70 -0.14 mg/m3. As observed, the lowest and highest exposure was obtained for the admission unit and sandstone, respectively. In general, it can be inferred that in all studied occupation positions, the exposure level was higher than the recommended standard (0.25 mg/m3). As can be seen, the carcinogenic risk level for the exposed workers was in the range 2-26/1000. The results of risk assessment showed that the highest risk level was related to the stamping machine operator unit and the lowest was related to the administrative unit. Conclusion: Therefore, the workers working in high-risk units such as stamping machine operator and stone separation operator are more likely to suffer from adverse health complications such as silicosis, lung cancer and other respiratory complications. https://japh.tums.ac.ir/index.php/japh/article/view/315 https://japh.tums.ac.ir/index.php/japh/article/download/315/288