30 CFR § 56.5005
Control of exposure to airborne contaminants.
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. See MSHA's Program Policy Manual
(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. See MSHA's Program Policy Manual
[60 FR 30398, June 8, 1995; 60 FR 33719, June 29, 1995; 60 FR 35692, July 11, 1995]