Work-Related Lung Disease (WoRLD) Surveillance System

Table 3-18. Respirable quartz: Geometric mean exposures and percent exceeding designated occupational exposure limits by MSHA coal mine district and state, MSHA inspector and mine operator samples, 1982–2003

- indicates incalculable field.PEL - permissible exposure limitREL - recommended exposure limitGM - geometric meanmg/m³ - milligrams per cubic meterMRE - Mining Research EstablishmentMSHA - Mine Safety and Health Administration
*Samples selected based on the respirable dust level and MSHA PEL (2 mg/m³ MRE or adjusted PEL).

Note:  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. See appendices for sourc

Source:  MSHA coal mine inspector and mine operator quartz data.

Archived Versions:

2002T03-18