Exposure, health effects and control of respirable crystalline silica in Queensland quarries

This paper presents findings of an ongoing study of respirable crystalline silica (RCS) exposure in quarries in Queensland. Twenty-six quarry workers from five quarries were monitored for RCS. A major area of concern was that the occupational exposure standard (0.1 mg/m3) was exceeded at four of the five quarries monitored and two measurements exceeded 0.25 mg/m (these high measures were for an excavator saw operator and a stone mason). Spirometry testing indicated moderate obstruction of airways for some workers. An analysis of the real-time dust monitoring showed that control measures, such as air-conditioned vehicle cabins, are not necessarily effective in preventing exposure to RCS. Preliminary results from the installation of an air cleaning device (RESP A(TM)) demonstrated the potential for reducing cabin exposure to RCS.