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Control of exposures to crystalline silica in stone monument manufacturing.

Kurimo-R; Blade-L; William-H
American Industrial Hygiene Conference and Exposition, June 2-7, 2001, New Orleans, Louisiana. Fairfax, VA: American Industrial Hygiene Association, 2001 Jun; :56
National Institute for Occupational Safety and Health (NIOSH) researchers conducted a field survey at a small manufacturer of stone monuments (mainly cemetery markers) to characterize workers' exposures to respirable crystalline silica and to evaluate exposure control methods. These exposures result from the use of abrasive blasting for engraving and texturing, since the abrasive agent and/or the stone may contain crystalline silica. Partial-workshift air sampling, covering three- to six-hour periods during which abrasive blasting was performed, revealed breathing zone concentrations between 19 and 43 micrograms of respirable crystalline silica per cubic meter of air (ug/m3), below the NIOSH recommended exposure limit (REL) of 50 ug/m3. However, since the abrasive blasting was done on a part-time basis with time allotted for preparatory tasks, and substantial portions of the sampling periods included these other tasks, full-shift exposures could be significantly greater at a similar facility where blasting is performed continuously. The primary engineering dust-control measure employed - a commercially available, exhausted, automated-blasting enclosure with a screened opening for viewing - was evaluated by measuring parameters such as face velocities (which were at least 160 feet per minute), using smoke tubes, and conducting real-time particulate monitoring synchronized with videotaping. The results revealed that this system effectively controlled the dust generated during automated blasting. The real-time video monitoring also revealed deficiencies in the operation, including the use of a compressed-air hose during cleanup, and an abrasive agent recycle chute that was not enclosed, substantially contributed to the measured exposures. Correction of these minor problems can maintain exposures below the NIOSH REL even if continuous blasting is conducted.
Workers; Work-environment; Exposure-levels; Respirable-dust; Respiratory-irritants; Silicates; Silica-dusts; Quartz-dust; Abrasive-blasting; Abrasives; Particulates; Particulate-dust; Stone-processing; Stone-products; Engineering-controls; Environmental-control-equipment; Control-technology; Exposure-levels; Air-sampling; Breathing-zone
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American Industrial Hygiene Conference and Exposition, June 2-7, 2001, New Orleans, Louisiana
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division