[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: 30CFR71.702]

[Page 439]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 71--MANDATORY HEALTH STANDARDS--SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES--Table of Contents
 
                    Subpart H--Airborne Contaminants
 
Sec. 71.702  Asbestos dust standard; measurement.

    (a) The 8-hour average airborne concentration of asbestos dust to 
which miners are exposed shall not exceed two fibers per cubic 
centimeter of air. Exposure to a concentration greater than two fibers 
per cubic centimeter of air, but not to exceed 10 fibers per cubic 
centimeter of air, may be permitted for a total of 1 hour each 8-hour 
day. As used in this subpart, the term asbestos means chrysotile, 
amosite, crocidolite, anthophylite asbestos, tremolite asbestos, and 
actinolite asbestos but does not include nonfibrous or nonasbestiform 
minerals.
    (b) The determination of fiber concentration shall be made by 
counting all fibers longer than 5 micrometers in length and with a 
length-to-width ratio of at least 3 to 1 in at least 20 randomly 
selected fields using phase contrast microscopy at 400-450 
magnification.

[41 FR 10223, Mar. 10, 1976. Redesignated at 45 FR 80756, Dec. 5, 1980]