[Code of Federal Regulations]
[Title 30, Volume 1]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 30CFR56.5001]

[Page 266-267]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 56--SAFETY AND HEALTH STANDARDS--SURFACE METAL AND NONMETAL MINES--Table of Contents
 
               Subpart D--Air Quality and Physical Agents
 
Sec. 56.5001  Exposure limits for airborne contaminants.

                               Air Quality


    Except as permitted by Sec. 56.5005--
    (a) Except as provided in paragraph (b) of this section, the 
exposure to airborne contaminants shall not exceed, on the basis of a 
time weighted average, the threshold limit values adopted by the 
American Conference of Governmental Industrial Hygienists, as set forth 
and explained in the 1973 edition of the Conference's publication, 
entitled ``TLV's Threshold Limit Values for Chemical Substances in 
Workroom Air Adopted by ACGIH for 1973,'' pages 1 through 54, which are 
hereby incorporated by reference and made a part hereof. This 
publication may be obtained from the American Conference of Governmental 
industrial Hygienists by writing to the Secretary-Treasurer, P.O Box 
1937, Cincinnati, Ohio 45201, or may be examined in any Metal and 
Nonmetal Mine Safety and Health District Office of the Mine Safety and 
Health Administration. Excursions above the listed thresholds shall not 
be

[[Page 267]]

of a greater magnitude than is characterized as permissible by the 
Conference.
    (b) The 8-hour time weighted average airborne concentration of 
asbestos dust to which employees are exposed shall not exceed 2 fibers 
per milliliter greater than 5 microns in length, as determined by the 
membrane filter method at 400-450 magnification (4 millimeter objective) 
phase contrast illumination. No employees shall be exposed at any time 
to airborne concentrations of asbestos fibers in excess of 10 fibers 
longer than 5 micrometers, per milliliter of air, as determined by the 
membrane filter method over a minimum sampling time of 15 minutes. 
``Asbestos'' is a generic term for a number of hydrated silicates that, 
when crushed or processed, separate into flexible fibers made up of 
fibrils. Although there are many asbestos minerals, the term 
`'asbestos'' as used herein is limited to the following minerals: 
chrysotile, amosite, crocidolite, anthophylite asbestos, tremolite 
asbestos, and actinolite asbestos.
    (c) Employees shall be withdrawn from areas where there is present 
an airborne contaminant given a ``C'' designation by the Conference and 
the concentration exceeds the threshold limit value listed for that 
contaminant.

[50 FR 4054, Jan. 29, 1985, as amended at 60 FR 35695, July 11, 1995]