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Health hazard evaluation report: HETA-2001-0461-2889, The Concrete Revolution, Denver, Colorado.

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, HETA 2001-0461-2889, 2003 Jan; :1-11
The National Institute for Occupational Safety and Health (NIOSH) received a management request from The Concrete Revolution in Denver, Colorado, to evaluate potential occupational exposure hazards in the manufacture of custom concrete counter tops. Five site visits were made to the plant between April and October 2002. Exposure assessments were conducted for noise, respirable crystalline silica, respirable dust (or particulates not otherwise regulated, respirable fraction), and asbestos fibers. Full shift exposures to noise were less than the NIOSH recommended exposure level of 85 decibels on the A-weighted scale. Personal breathing zone (PBZ) exposures to respirable crystalline silica (as quartz and cristobalite) were below the limit of detection (LOD) for quartz in one sample and at trace concentrations [between the LOD and the limit of quantitation (LOQ)] for five other samples. Cristobalite was never detected above the LOD nor were airborne asbestos fibers. Certain elements (metals) were detected in samples of settled dusts from drying rooms 1 and 2 but were in very low concentrations. Quartz was also detected in settled dust samples in concentrations of 2.0 to 3.3%. Three area and six PBZ air samples collected for respirable dust ranged in concentration from 1.8 to 10 milligrams per cubic meter of air (mg/m3). One of these samples exceeded the OSHA Permissible Exposure Limit for respirable dust of 5 mg/m3. At the time of the NIOSH survey, management and employees at the Concrete revolution were refining work practices and considering modifications to exhaust ventilation in the drying rooms to reduce particulate exposures. Work practice, housekeeping, and ventilation recommendations are provided on pages 6-7 of this report. Occupational exposure to noise, respirable crystalline silica, asbestos and metals were all below established occupational health criteria at the time of this survey. One of nine samples for respirable dust exceeded the Occupational Safety and Health Administration (OSHA) criterion of 5 milligrams per cubic meter of air as an 8-hour time-weighted average. Recommendations are provided to modify work practices and consider ventilation changes to better control dusts while patching and finishing custom concrete counter tops.
Region-8; Hazard-Confirmed; Noise; Respirable-dust; Concretes; Silica-dusts; Quartz-dust; Asbestos-dust; Asbestos-cement; Particulate-dust; Particulates; Work-practices; Ventilation-systems; Ventilation; Author Keywords: Concrete products; concrete; counter tops; silica; respirable dust; Denver
14808-60-7; 1332-21-4; 14464-46-1
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Field Studies; Hazard Evaluation and Technical Assistance
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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