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


- indicates incalculable field.    PEL - permissible exposure limit    REL - recommended exposure limit    GM

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 cristobali

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

Reference Number: 2008-339

Date Posted: June 2008

Archived Version