An Evaluation of Compliance with Occupational Exposure Limits for Crystalline Silica (Quartz) in Ten Georgia Granite Sheds

Since the 1920s, industrial hygiene studies have documented granite shed workers' exposures to crystalline silica, and the data from these studies have contributed to a better understanding of the relationship between silica exposures and adverse health effects, such as silicosis. The majority of these studies were conducted in the Barre, Vermont, granite sheds. However, a second major granite processing region is located in Elberton, Georgia, where approximately 1800 workers are employed in 150 granite sheds and 45 quarries. The current study reports the exposures of 40 workers in 10 granite sheds in Elberton, Georgia. The arithmetic mean exposure to silica for all monitored employees was 0.052 mg/m 3 . Employees were classified into one of seven job task groups. The job task group with the greatest exposure was the top polish group, which had a mean exposure of 0.085 mg/m 3 . Among the top polish workers, the greatest percentage of exposures above the Occupational Safety and Health Administration's permissible exposure limit (OSHA PEL) occurred among the workers who used dry grinders. Wet methods were effective in reducing these exposures to below the OSHA PEL. The mean exposure of Elberton granite shed workers was less than the OSHA PEL, but was not below the threshold limit value of the American Conference of Industrial Hygienists (ACGIH ® TLV ® ), which was lowered in the year 2000 to 0.05 mg/m 3 . The Elberton granite shed workers provide a valuable cohort for research on the effects of exposure to crystalline silica at levels between the ACGIH TLV and the OSHA PEL. They are a relatively permanent worker population, are concentrated geographically, and have a quantitatively documented exposure to crystalline silica over the past twenty years.

Keywords:

• Silica Exposures
• Granite Sheds
• Silica Controls