Work-Related Lung Disease (WoRLD) Surveillance System

Respirable quartz: Number of samples, geometric mean exposures, and percent exceeding designated occupational exposure limits by industry, MSHA inspector and mine operator and OSHA samples, 1993–2003

CIC - Census Industry CodePEL - permissible exposure limitREL - recommended exposure limit GM - geometric meanMRE - Mining Research Establishmentn.e.c. - not elsewhere classified
MSHA - Mine Safety and Health AdministrationOSHA - Occupational Safety and Health Administration
* includes industries with no samples exceeding the REL or industries with less than 10 samples.
† Geometric mean reported in mg/m3 MRE. Samples selected based on the respirable dust level and MSHA PEL (2 mg/m3 MRE or adjusted PEL).
‡ The MSHA respirable coal mine quartz exposure data and the NISOH REL for respirable quartz cannot be compared to each other because they are based on difference sampling criteria.

Note:  Before March 1, 1989 and after March 22, 1993, the OSHA PEL is [(10 mg/m3) /(% quartz + 2)], for respirable dust containing at least 1 percent quartz. From March 1, 1989 to March 22, 1993, the OSHA PEL was 0.1 mg/m3 for respirable quartz. For coal mining, the MSHA PEL is 2 mg/m3 MRE for respirable dust containing less than or equal to 5 percent quartz. The PEL is adjusted using the formula [(10 mg/m3 MRE) / (% quartz)] for respirable dust containing greater than 5 percent quartz; for metal/nonmetal mining, the MSHA PEL is [(10 mg/m3) / (% quartz + 2)] for respirable dust containing at least 1 percent quartz. The NIOSH REL is 0.05 mg/m3. See appendices forsource description, methods, and industry codes.

Source:  MSHA metal/nonmetal and coal mine inspector and mine operator quartz data. OSHA Integrated Management Information System.

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