Introduction: Occupational exposure to crystalline silica increases the risk of lung cancer and restrictive lung disease with extensive fibrosis. Silica dust is a major health hazard in foundry factories. The aim of this study was to determine core making workers’ exposure to respirable crystalline silica dust in a foundry factory.

Material and Method: This cross-sectional study was conducted in core-making unit of a foundry factory in 2015. Occupational exposure of 55 workers to respirable crystalline silica aerosols was evaluated by using the improved NIOSH7602 method in core-making unit. Risk assessments for silicosis and excess lifetime risk of mortality from lung cancer were done according to Manettej and Rice models, respectively. Data was analyzed with Spss19 software.

Result: The mean of respirable crystalline silica dust was 0.246 ± 0.351 (mg/m3). All  workers’ exposure to respirable crystalline silica was higher than recommended occupational exposure limits. Silicosis mortality risk and excess lifetime risk of mortality from lung cancer were estimated in the range of 6-63 and 65 per thousand people, respectively.

Conclusion: The mean of workers’ exposure to respirable crystalline silica was higher than recommended occupational exposure standards in core making unit. The risk assessment of silicosis mortality and excess lifetime risk of mortality from lung cancer were higher than acceptable levels of risk.