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[December 13, 2004 (Volume 69, Number 238)]
[Unified Agenda]
[Page 73468-73469]

Department of Labor (DOL)
Prerule Stage

Mine Safety and Health Administration (MSHA)



Priority: Other Significant

Legal Authority: 30 USC 811; 30 USC 813

CFR Citation: 30 CFR 70; 30 CFR 71; 30 CFR 90; 30 CFR 72; 30 CFR 58; . . .

Legal Deadline: None

Abstract: Current standards limit exposures to quartz (crystalline silica) in respirable dust. The coal mining industry standard is based on the formula 10mg/m3 divided by the percentage of quartz where the quartz percent is 5.0 percent or greater calculated as an MRE equivalent concentration. The metal and nonmetal mining industry standard is based on the 1973 American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values formula: 10 mg/m3 divided by the percentage of quartz plus 2. Overexposure to crystalline silica can result in some miners developing silicosis which may ultimately be fatal. Both formulas are designed to maintain exposures to 0.1 mg/m3 (100 ug) of silica. The Secretary of Labor's Advisory Committee on the Elimination of Pneumoconiosis Among Coal Mine Workers made several recommendations related to reducing exposure to silica. NIOSH and ACGIH recommend a 50ug/ m3 exposure limit for respirable crystalline silica. MSHA is considering several options to reduce miners' exposure to crystalline silica.


Action                            Date                      FR Cite


Request for Information         12/00/04
Regulatory Flexibility Analysis Required: Undetermined

Government Levels Affected: None

Agency Contact: Marvin W. Nichols Jr., Director, Office of Standards,
Department of Labor, Mine Safety and Health Administration, Room 2352,
1100 Wilson Boulevard, Room 2350, Arlington, VA 22209
Phone: 202 693-9440
Fax: 202 693-9441

RIN: 1219-AB36