Work-Related Lung Disease (WoRLD) Surveillance System

Respirable cristobalite: Geometric mean exposures and percent exceeding designated occupational exposure limits, MSHA and OSHA samples, 1979–2003

- indicates incalculable field.PEL - permissible exposure limitREL - recommended exposure limitGM - geometric mean mg/m3 - milligrams per cubic meterMSHA - Mine Safety and Health AdministrationOSHA - Occupational Safety and Health Administration

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 and methods.

Source:  MSHA metal/nonmetal mine data. OSHA Integrated Management Information System.

Archived Versions:

2002T03-21