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In-depth survey report: partnering to control dust from fiber-cement siding, St. Mary's Hospital, Greensboro, Georgia.

Qi C; Echt A; Hirst DVL
Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, EPHB 358-12a, 2013 Nov; :1-28
Background: Workplace exposure to respirable crystalline silica can cause silicosis, a progressive lung disease marked by scarring and thickening of the lung tissue. Quartz is the most common form of crystalline silica. Crystalline silica is found in several construction materials, such as brick, block, mortar and concrete. Construction tasks that cut, break, grind, abrade, or drill those materials have been associated with overexposure to dust containing respirable crystalline silica. Fiber-cement products can contain as much as 50% crystalline silica, and cutting this material has been shown to cause excessive exposures to respirable crystalline silica. NIOSH scientists are conducting a study to develop engineering control recommendations for respirable crystalline silica from cutting fiber-cement siding. This site visit was part of that study. Assessment: NIOSH staff visited the St. Mary's Hospital construction site in Greensboro, Georgia on June 18th, 19th, and 20th, 2013. During those visits, they performed industrial hygiene sampling which measured the exposures to respirable dust and respirable crystalline silica of four workers who cut and installed fiber-cement siding during the construction of the hospital. An engineering control measure was implemented by connecting a dust-collecting circular saw to a regular shop vacuum. The shop vacuum provided a local exhaust ventilation to remove the dust generated from cutting fiber-cement siding using the dust-collecting circular saw. The NIOSH scientists also monitored the wind speed and direction at the site, and collected data about the work process in order to understand the conditions that led to the measured exposures. Results: Air sampling for respirable crystalline silica showed that on all three days, all four workers' 10-hour time weighted average (TWA) exposures to respirable quartz (the most common form of crystalline silica) were in the range of 0.001 to 0.015 mg/m3, which were considerably lower than both the NIOSH Recommended Exposure Limit (REL) of 0.05 mg/m3 and the Threshold Limit Value (TLVs) of 0.025 mg/m3 by American Conference of Governmental Industrial Hygienists (ACGIH). Their exposures were also considerably lower than the OSHA Permissible Exposure Limit (PEL) for respirable dust that contains greater than 1% quartz, with the 8-hour TWA exposure during the sampling periods in the range of 0.04 to 0.14 mg/m3. Conclusions and Recommendations: The exposure levels indicated that the evaluated engineering control measure was effective in reducing the workers' exposures to concentrations below both the NIOSH REL and ACGIH TLV for respirable quartz, and the OSHA PEL for respirable dust. This engineering control measure has the potential to provide an effective, simple and low cost solution for workers cutting fiber-cement siding.
Region-4; Control-technology; Engineering-controls; Construction-materials; Construction-industry; Construction-workers; Dusts; Silica-dusts; Fibrous-dusts; Respirable-dust; Dust-control; Dust-control-equipment; Respiratory-protective-equipment; Respiratory-protection; Quartz-dust; Cements; Concretes; Cutting-tools; Sampling; Vacuum-equipment; Ventilation; Exhaust-ventilation; Control-equipment; Control-systems; Dust-collection; Work-practices; Air-samples; Air-sampling; Time-weighted-average-exposure; Exposure-levels; Exposure-limits; Author Keywords: Siding Contractors; Respirable dust; Silica; Fiber-cement siding; Engineering control
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Field Studies; Control Technology
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National Institute for Occupational Safety and Health
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division