Between 1980 and 1992, compliance officers of the Occupational Safety and Health Administration in the United States measured respirable quartz in 1655 inspections in 255 industries. In 133 of the 255 industries where respirable quartz was measured, the average severity value was less than one, indicating average exposures below the permissible exposure limit, and in 48% the permissible exposure limit for silica was exceeded. Among industries where more than 10 facilities were inspected, the most severe respirable quartz exposures were found in fabricated structural metal; painting and paper hanging; nonresidential construction; shipbuilding and repair; masonry and other stone work; bridge; tunnel and elevated highway construction; metal coating, engraving and allied services; and special trades contractors.

Key terms brick; clay; construction; foundry; glassware; metal fabrication; permissible exposure limit