A Scoping Review on Occupational Exposure of Silica and Asbestos among Industrial Workers in Thailand

Abstract

Pneumoconiosis is one of the most common occupational lung diseases in Thailand and worldwide. Workplace exposure to asbestos and silica is the main contributor to the prevalence of occupational pneumoconiosis. The aim of this study was to review the prevalence of occupational exposure to asbestos and silica among industrial workers in Thailand. A scoping literature review searched MEDLINE and universities in Thailand. The results from screening 113 were 11 studies selected for further review. Ten studies were cross-sectional and only one study was a retrospective cohort study. Four studies focused on asbestos exposure, whereas seven studies measured silica exposure. From four asbestos exposure studies, three studies showed a higher than standard exposure limit. From seven studies on silica exposure, four studies showed the measured exposure was above the standard level.  However, the prevalence of exposure among people working in low-risk areas was not presented. The standard protocol of asbestos and silica exposure measurement was reported. The results showed that the average asbestos and silica exposure exceeded occupational exposure limits stated in either international or national guidelines. The highest level of asbestos exposure was found in a brake pad factory (9.95 fibres/cc). The highest amount of total silica dust was reported in a stone grinding factory (24.3 mg/m3). Prevention measures and active surveillance programs should be in place for all populations at risk. National surveys on occupational exposure of asbestos and silica are needed to explore current industrial practices and their compliance according to the standard national exposure limit.