Industrial hygiene survey of respirable crystalline silica dust exposure in the ready-mixed concrete industry.
NIOSH 1995 Sep; :1-13
NIOSH has undertaken this study to investigate respirable crystalline silica exposure in the ready-mixed concrete industry. Crystalline silica occurs in three distinct types - quartz, cristobalite, and tridymite, with quartz being the predominant type of crystalline silica found at most workplaces. Cristobalite and tridymite may be somewhat more potent than quartz in causing silicosis. Cristobalite and tridymite are formed from quartz when it is exposed to high temperatures (1470 and 870 degrees centigrade, respectively). These two forms of crystalline silica are not dealt with for the purposes of this investigation, since they usually occur only in the volcanic rock of California, Colorado, and Mexico. The central ingredients in concrete have been the same since 1824, with one ingredient being silica sand. NIOSH has attempted - through this investigation - to learn the extent of employees' exposure to airborne dust containing respirable crystalline silica. This pilot study examined six ready-mix operations to gauge employee exposures to respirable crystalline silica.
Concretes; Silica-dusts; Respirable-dust; Exposure-assessment; Exposure-levels; Cements; Fly-ash; Sampling; Quartz-dust; Stone-processing; Industrial-exposures; Exposure-limits; Calcium-compounds; Silicosis; Analytical-Method
National Institute for Occupational Safety and Health, Division of Respiratory Disease Studies, Environmental Investigations Branch, 1095 Willowdale Road, Morgantown, WV 26505
14808-60-7; 1305-62-0; 1305-78-8
NTIS Accession No.
National Institute for Occupational Safety and Health