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DOL/MSHA RIN: 1219-AB36 Publication ID: Spring 2013 
Title: Respirable Crystalline Silica  
Abstract: Current standards limit exposures to quartz (crystalline silica) in respirable dust. 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, an irreversible but preventable lung disease, which ultimately may be fatal. The formula is designed to limit exposures to 0.1 mg/m3 (100 ug) of silica. NIOSH recommends a 50 ug/m3 exposure limit for respirable crystalline silica. MSHA will publish a proposed rule to address miners' exposure to respirable crystalline silica. 
Agency: Department of Labor(DOL)  Priority: Other Significant 
RIN Status: Previously published in the Unified Agenda Agenda Stage of Rulemaking: Proposed Rule Stage 
Major: No  Unfunded Mandates: No 
CFR Citation: 30 CFR 58 
Legal Authority: 30 USC 811 
Legal Deadline:  None
Timetable:
Action Date FR Cite
NPRM  12/00/2013   
Regulatory Flexibility Analysis Required: Undetermined  Government Levels Affected: Local, State 
Small Entities Affected: Businesses, Governmental Jurisdictions  Federalism: No 
Included in the Regulatory Plan: No 
RIN Information URL: www.msha.gov/regsinfo.htm   Public Comment URL: www.regulations.gov  
RIN Data Printed in the FR: No 
Agency Contact:
George F. Triebsch
Director, Office of Standards, Regulations, and Variances
Department of Labor
Mine Safety and Health Administration
1100 Wilson Boulevard, Room 2350,
Arlington, VA 22209
Phone:202 693-9440
Fax:202 693-9441
Email: triebsch.george@dol.gov