| Organization | Standard | Reference | 
|---|
| Mine Safety and Health Administration (MSHA) STANDARD-air | time-weighted average 50 mppcf | DTLWS* 3,33,1973 | 
| Occupational Exposure Limit IN ARGENTINA, BULGARIA, COLOMBIA, JORDAN check ACGIH TLV; |  |  | 
| Occupational Exposure Limit IN SINGAPORE, VIETNAM check ACGIH TLV |  |  | 
| Occupational Exposure Limit-BELGIUM | time-weighted average 10 mg/m3, MAR2002 |  | 
| Occupational Exposure Limit-FINLAND | time-weighted average 1 mg/m3, resp. dust, NOV2011 |  | 
| Occupational Exposure Limit-FINLAND | time-weighted average 5 mg/m3, inhal. dust, NOV2011 |  | 
| Occupational Exposure Limit-HUNGARY | time-weighted average 10 mg/m3, SEP2000 |  | 
| Occupational Exposure Limit-JAPAN | Occupational Exposure Limit 1 mg/m3 (resp. dust), 4 mg/m3 (total dust), MAY2012 |  | 
| Occupational Exposure Limit-KOREA | time-weighted average 10 mg/m3, 2006 |  | 
| Occupational Exposure Limit-MEXICO | time-weighted average 10 mg/m3;short term exposure limit 20 mg/m3 (inhalable), 2004 |  | 
| Occupational Exposure Limit-NEW ZEALAND | time-weighted average 10 mg/m3 (inspirable dust), JAN2002 |  | 
| Occupational Exposure Limit-PERU | time-weighted average 10 mg/m3, JUL2005 |  | 
| Occupational Exposure Limit-SWITZERLAND | MAK-week 5 mg/m3, inhal dust, sen, JAN2011 |  | 
| Occupational Exposure Limit-THE NETHERLANDS | MAC-TGG 10 mg/m3, 2003 |  | 
| Occupational Exposure Limit-UNITED KINGDOM | time-weighted average 4 mg/m3 (resp. dust), OCT2007 |  | 
| Occupational Exposure Limit-UNITED KINGDOM | time-weighted average 10 mg/m3 (inhal. dust), OCT2007 |  | 
| Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Construction) | 8H time-weighted average 50 mppcf | CFRGBR 29,1926.55,1994 | 
| Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Federal Contractors) | 8H time-weighted average 50 mppcf | CFRGBR 41,50-204.50,1994 | 
| Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (General Industry) | 8H time-weighted average 15 mg/m3, total dust | CFRGBR 29,1910.1000,1994 | 
| Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (General Industry) | 8H time-weighted average 5 mg/m3, respirable fraction | CFRGBR 29,1910.1000,1994 | 
| Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Shipyards) | 8H time-weighted average 50 mppcf | CFRGBR 29,1915.1000,1993 |