Health Risks Assessment of Occupational Exposure to Respirable Crystalline Silica in Silica Crushing, Ceramics, Foundry, and Cement Industries in Hamadan, Iran

Background and Objective: Exposure to respirable crystalline silica (RCS) causes silicosis, lung cancer, autoimmune diseases of rheumatoid arthritis or systemic scleroderma, and benign respiratory system diseases. The risk assessment has an important scientific role in the control of occupational diseases by estimating the risk of death and determining the dose-response relationship. The present study aimed to evaluate the health risks of occupational exposure to RCS in workers in silica crushing, ceramics, foundry, and cement industrial sectors in Hamadan, Iran. Materials and Methods: In this cross-sectional study, occupational exposure to RCS was investigated in 15 job titles. The potential lifetime cancer risk (LCR) was calculated by considering some factors, such as work experience, duration and frequency of exposure, lifetime and the reference rate of inhalation exposure, and the risk coefficient (hazard quotient: HQ), using the Olawoyin model. Results: The lowest levels of LCR (approximately 8 cases per 1.000.000 workers) and HQ (0.093) were obtained in the job title of Furnace (L) in the foundry, and the highest levels of LCR (approximately 2 cases per 1000 workers) and HQ (26.41) were observed in the job title of Supervisor (D) in silica crushing. The HQ levels in nine job titles were higher than the recommended allowable levels, while in other job titles, they were lower. Moreover, the results indicated a direct relationship between LCR and HQ levels in the studied job titles. Conclusion: Considering the important and influential role of the parameters used to evaluate LCR and the possibility of HQ determination by the Olawoyin model, it is recommended that this model be employed to evaluate health risks in occupational exposure to RCS in future studies.