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Work-Related Lung Disease Surveillance System (eWoRLD)

Silicosis: Respirable Cristobalite Exposures (Archive)

Respirable cristobalite: Geometric mean exposures and percent exceeding designated occupational exposure limits, MSHA and OSHA samples, 1979-1999
Table showing Respirable cristobalite: Geometric mean exposures and percent exceeding designated occupational exposure limits, MSHA and OSHA samples, 1979-1999

- indicates incalcuable field
PEL - permissible exposure limitREL - recommended exposure limitGM - geometric mean

Note:  Before March 1, 1989 and after March 22, 1993, the OSHA PEL is [(5 mg/m3) / (% cristobalite + 2)], for respirable dust containing at least 1 percent cristobalite. From March 1, 1989 to March 22, 1993, the OSHA PEL was 0.05 mg/m3 for respirable cristobalite. For metal/nonmetal mining, the MSHA PEL is [(5 mg/m3) / (% cristobalite + 2)] for respirable dust containing at least 1 percent cristobalite. The NIOSH REL is 0.05 mg/m3. See appendices for source description, methods, and agents.

Source:  Mine Safety and Health Administration (MSHA) metal/nonmetal mine data. Occupational Safety and Health Administration (OSHA) Integrated Management Information System.

Reference Number: 2002T03-21

Date Posted: May 2003

Most Recent Version:
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