Although often thought of as an historical issue, respirable crystalline silica (RCS) remains one of the most common occupational exposures worldwide.1,2 Silicosis is a progressive and irreversible fibrotic lung disease,…
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Heavy exposure to dust containing very fine particles of silica has long been known to cause silicosis or a scarring of the lung. From many studies conducted overseas, it has been found that even low levels of exposure also increase the risk of lung cancer and kidney disease. We measured the levels of exposure of construction workers, mainly when cutting or grinding concrete. We found that a sizeable proportion of construction workers did have exposure that was hazardous, and recommend that dust levels need to be reduced to prevent disease.
To assess personal exposure to respirable dust and respirable crystalline silica (RCS) in New Zealand construction workers.
In a pilot study, 39 personal samples were collected from a cross-section of workers engaged in a range of tasks performed on construction sites that were expected to entail exposure to respirable crystalline silica. Nine static samples were taken at locations adjacent to these tasks. Particle size-selective sampling heads were used to collect the respirable fraction of airborne particulates. Dust concentrations were determined gravimetrically, while crystalline silica was analysed using x-ray diffraction.
Almost half of the personal crystalline silica samples exceeded the New Zealand Workplace Exposure Standard (NZ WES), while 56% exceeded the more stringent international recommendation (ACGIH TLV). The tasks associated with the highest RCS levels were concrete grinding and cutting. Two of four static samples collected close to (silica-containing) Linea board cutting exceeded the ACGIH TLV for RCS, indicating the potential for bystander exposure.
A large proportion of workers performing common tasks in the construction industry may be exposed to levels of respirable dust and crystalline silica exceeding national standards and international recommendations. These results suggest that workers in this industry may be at risk of developing silica-related diseases, including silicosis, lung cancer, COPD and chronic renal disease. Action is required to improve dust control to reduce silica exposure and the associated health risks.