Objectives To (a) develop a surveillance system for silicosis (b)estimate prevalence of silicosis and respiratory disorders among stone carversand (c) develop a guideline for screening for silicosis.

Method This was a cross-sectional, descriptive study of 1257 stone carvers. Data were collected between July and October, 2012. The 767 participants in the study were classified by job categories. Exposure indices were constructed. Health outcomes (including job description, respiratory symptoms and chest radiographs) were assessed and confirmed bydiagnosis by a B reader.

Results Of the total population, 767 underwent chest radiographs (age24 to 75 years; 97.1% male). The duration of exposure was between 2 and 30 years. The prevalence of radiographic change was 8.9%(68 subjects). There were 66 subjects with parenchymal lesions and profusion (> grade 1/0 as per ILO classification). Two subjects have pleural abnormalities. Importantly, 55 cases among 68 with radiographic abnormalitieswere compatible with tuberculosis; 32 of whom showed no clinical evidence of tuberculosis.

Conclusions The diagnostic differentiation between silicosis and tuberculosis ischallenging; consequently, discrepancies can arise when reporting the prevalence of the two diseases. Our research group isdeveloping CPG for screening silicosis forreferral to a clinician in chest medicine. The remaining at-risk population will be examined by chest X-ray in July 2013 and the hazard surveillance and exposure to silica performed next.