Occupational exposure to crystalline silica in artificial stone processing

Respirable Crystalline Silica (RCS) is a hazardous substance with known effects that can be well correlated with exposure levels that still persist in many traditional sectors, such as construction or stone processing. In the past decade, exposure scenarios for RCS have been found in the sector of artificial stone processing. The aim of this study is to evaluate the levels of RCS in facilities specialized in the production of artificial stone countertops and other accessories for the furnishing of kitchens, bathrooms, and offices after the introduction of some preventive technical measures such as wet processing or local exhaust ventilation systems. The study involved 51 subjects in four facilities. Personal silica exposure assessment was carried out using GS3 cyclones positioned in the breathing zone during the work shift. Quantitative determination of silica was carried out by X-ray diffraction analysis. Respirable dust levels were in the range 0.046-1.154 mg/m(3) with RCS levels within the range <0.003-0.098 mg/m(3). The highest exposure was found in dry finishing operations. Although there was a remarkable reduction in RCS exposure levels compared to what was observed in the past before the introduction of preventive measures, the data still showed hazardous exposure levels for some of the monitored activities.