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Promoting early exposure monitoring for respirable crystalline silica: taking the laboratory to the mine site.

Cauda E; Miller A; Drake P
J Occup Environ Hyg 2016 Mar; 13(3):D39-D45
Much has been done in recent years in the area of monitoring exposure to aerosols in occupational environments, specifically in the mining industry, with the goal of obtaining more accurate and timely information. The monitoring solutions developed for respirable coal dust, diesel particulate matter, and respirable dust enhanced by video features are aimed at gathering near-real-time information of the aerosol concentration levels during the shift. Unfortunately these solutions do not address the monitoring of respirable crystalline silica (RCS) in the mining environment. The exposure to RCS can lead over time to debilitating respiratory diseases affecting the health of workers, such as silicosis and lung cancer. The approach to occupational exposure monitoring for RCS has not changed substantially in the last few decades and entails collecting a dust sample with a respirable sampler and submitting the sample to an accredited laboratory for analysis using established analytical techniques, infrared and x-ray diffraction (XRD), that have been tested and assessed extensively. Aside from the cost of analysis, the main limitation of the current approach is the lack of timely information to the industrial hygienist or other responsible person on site. The time between sample collection and interpretation of the results of the analysis at the mine site limits the possibility for occupational health professionals to promptly address overexposures or to request the adjustment of a control technology. In addition, the results could have little or no value in the case of mobile mining operations because the operation has often moved to a new location before exposure results are available, and RCS concentrations might change due to variation in local geology. The use of the aforementioned innovative respirable dust monitoring solutions would not provide useful information on RCS, since they only record aerosol concentration, and the percent of crystalline silica in respirable mine dusts has been found to be variable so a correction factor can't be applied. For the above reasons, a solution is needed for on-site quantification of RCS in dust samples, and potential solutions are being investigated by the Office of Mine Safety and Health Research (OMSHR), a division of the National Institute for Occupational Safety and Health (NIOSH). When developed, the solutions will allow operators to estimate RCS immediately after sampling, resulting in more timely monitoring of RCS for self-assessment of compliance at the end of the shift, more effective engineering monitoring, and better evaluation of control technologies.
Monitoring-systems; Aerosols; Environmental-exposure; Exposure-levels; Risk-factors; Mining-industry; Coal-dust; Dust-particles; Dusts; Dust-exposure; Particulates; Diesel-emissions; Diesel-exhausts; Silicates; Silica-dusts; Respiration; Respiratory-irritants; Respiratory-system-disorders; Pulmonary-function; Pulmonary-system; Pulmonary-system-disorders; Silicosis; Lung; Lung-fibrosis; Lung-disease; Lung-disorders; Cancer; Sampling
14808-60-7; 7631-86-9
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Journal of Occupational and Environmental Hygiene
Page last reviewed: May 11, 2023
Content source: National Institute for Occupational Safety and Health Education and Information Division