Occupational Exposure to Crystalline Silica and Its Pulmonary Effects among Workers of a Cement Factory in Saveh, Iran

Objectives: This study aimed to assess exposure to crystalline silica and its relation with risk of pulmonary functional disorders among workers of a cement industry in Saveh, Iran.Methods: In this cross-sectional study, 62 samples of respirable dust were collected from breathing zone of workers in different sections of a 4-years-old cement factory in 2011. Determination ofrespirable dust concentrations carried out using gravimetric method according to the "National Institute for Occupational Safety and Health"(NIOSH) method no. 0600. Visible absorption spectrophotometry was used according to the NIOSH method no. 7601 to measure crystalline silica content of reparable dust samples.Spirometry test was also applied to assess workers’ pulmonary function parameters.Results: Range of site workers’ exposure to respirable fraction of cement dust was1.77 to 18.89 mg/m 3 , and their exposure to crystalline silica was at the range of 0.011 to 0.104 mg/m 3 . The highest levels of exposure to respirable dust and crystalline silica were observed in "raw mill”. Occupational exposure to crystalline silica in 57% of site samples exceeded theNIOSH REL (0.05 mg/m 3 ).The partial correlation test showed a significant relationship between workers’ exposure to crystalline silica and reduction in parameters such as FVC% and FEV1% (p-value<0.05).Conclusion: Exposure to crystalline silica can reduce the value of some pulmonary function parameters such as FVC% and FEV1% and cause restrictive pulmonary disorders. Therefore, control of workers’ exposure to crystalline silica, especially in units with highest level of crystalline silica concentration should primarily be considered.