Respirable coal mine dust: Geometric mean exposures and percent exceeding designated occupational exposure limits by MSHA coal mine district and state, MSHA inspector and mine operator samples, 1979–2003
- 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
Note: In coal mining, for respirable dust containing less than or equal to 5% quartz, the MSHA PEL is 2 mg/m3 MRE; for respirable dust containing greater than 5% quartz, the MSHA PEL is [(10 mg/m3 MRE) / (% quartz)]. The NIOSH REL of 1 mg/m3 MRE for respirable coal mine dust was adopted in September of 1995. Geometric means are reported in MRE equivalent. All samples are compared to the MSHA PEL for respirable coal mine dust containing less than or equal to 5% quartz, regardless of actual quartz content. See appendices for source description and methods.
Source: MSHA coal mine inspector and mine operator dust data.
