30 C.F.R. Subpart D—Air Quality and Physical Agents
Title 30 - Mineral Resources
Except as permitted by §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 1330 Kemper Meadow Drive, Attn: Customer Service, Cincinnati, OH 45240; http://www.acgih.org”, 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 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 (c) Employees shall be withdrawn from areas where there is present an airborne contaminant given a “C” designation by the Conference and the concentration exceeds the threshold limit value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; 71 FR 16667, Apr. 3, 2006] Dust, gas, mist, and fume surveys shall be conducted as frequently as necessary to determine the adequacy of control measures. Control of employee exposure to harmful airborne contaminants shall be, insofar as feasible, by prevention of contamination, removal by exhaust ventilation, or by dilution with uncontaminated air. However, where accepted, engineering control measures have not been developed or when necessary by the nature of work involved (for example, while establishing controls or occasional entry into hazardous atmospheres to perform maintenance or investigation), employees may work for reasonable periods of time in concentrations of airborne contaminants exceeding permissible levels if they are protected by appropriate respiratory protective equipment. Whenever respiratory protective equipment is used a program for selection, maintenance, training, fitting, supervision, cleaning, and use shall meet the following miminum requirements: (a) Respirators approved by NIOSH under 42 CFR part 84 which are applicable and suitable for the purpose intended shall be furnished and miners shall use the protective equipment in accordance with training and instruction. (b) A respirator program consistent with the requirements of ANSI Z88.2–1969, published by the American National Standards Institute and entitled “American National Standards Practices for Respiratory Protection ANSI Z88.2–1969,” approved August 11, 1969, which is hereby incorporated by reference and made a part hereof. This publication may be obtained from the American National Standards Institute, Inc., 25 W. 43rd Street, 4th Floor, New York, NY 10036; http://www.ansi.org”, or may be examined in any Metal and Nonmetal Mine Safety and Health District Office of the Mine Safety and Health Administration. (c) When respiratory protection is used in atmospheres immediately harmful to life, the presence of at least one other person with backup equipment and rescue capability shall be required in the event of failure of the respiratory equipment. [50 FR 4054, Jan. 29, 1985, as amended at 60 FR 30400, June 8, 1995; 60 FR 33723, June 29, 1995; 60 FR 35695, July 11, 1995; 71 FR 16667, Apr. 3, 2006] The following chemical substances shall not be used or stored except by competent persons under laboratory conditions approved by a nationally recognized agency acceptable to the Secretary. (a) Carbon tetrachloride. (b) Phenol, (c) 4-Nitrobiphenyl, (d) Alpha-naphthylamine, (e) 4,4-Methylene Bis (2-chloroaniline), (f) Methyl-chloromethyl ether, (g) 3,3 Dichlorobenzidine, (h) Bis (chloromethyl) ether, (i) Beta-napthylamine, (j) Benzidine, (k) 4-Aminodiphenyl, (l) Ethyleneimine, (m) Beta-propiolactone, (n) 2-Acetylaminofluorene, (o) 4-Dimethylaminobenzene, and (p) N-Nitrosodimethylamine.
Title 30: Mineral Resources
PART 56—SAFETY AND HEALTH STANDARDS—SURFACE METAL AND NONMETAL MINES
Subpart D—Air Quality and Physical Agents
Air Quality
§ 56.5001 Exposure limits for airborne contaminants.
§ 56.5002 Exposure monitoring.
§ 56.5005 Control of exposure to airborne contaminants.
§ 56.5006 Restricted use of chemicals.
