NIOSHA OSHA Particulate Mask Respirators: P100, N100, N99, N95

The Office of Health Compliance Assistance has received numerous questions over the last several weeks questioning the applicability, selection, and use of particulate respirators for workplace exposure to dusts, mists, and fumes. The purpose of this memorandum is to address current issues that have been raised regarding the use, selection, and applicability of the new classes of respirators certified under 42 CFR Part 84. In our September 6, 1995, memorandum to Regional Administrators entitled "Update: OSHA Enforcement Policy for Occupational Exposure to Tuberculosis" we stated the agency would accept these new particulate respirators for use against exposure to Mycobacterium tuberculosis. These respirators are also approved for protection against particulates in all other work environments including construction, maritime, agriculture and manufacturing.

Under the new NIOSH criteria, the filter materials for these respirators are tested at a flow rate of 85 L/minute for penetration by particles with a median aerodynamic diameter of approximately 0.3 um. Three categories of filter (N, R, and P) are designated, each with three levels of filter efficiency (95%, 99%, and 99.97%) for a total of nine respirator classes. The three levels of filter efficiency include the Type 100 (99.97% efficient), Type 99 (99% efficient), and the Type 95 (95% efficient). The classes of these air-purifying, particulate respirators certified under this classification are described in 42 CFR Part 84 Subpart K. (Volume 60 of the Federal Register page 30338, June 8, 1995.) This classification applies only to non-powered (negative pressure) respirators. Respirators certified under this classification replace the dust; dust, mist, fume; and HEPA respirators previously certified under 30 CFR Part 11. For powered air purifying respirators (PAPRs), HEPA filters remain available (42 CFR Part 84 Subpart kk).

The Type 95, Type 99, and Type 100 respirators, are approved for use against particulates by NIOSH and are accepted by OSHA for appropriate use in all work environments. As with other respiratory requirements, the employer must assure that employees required to wear respirators under any OSHA standard are part of a continuing and effective respiratory program as described in 29 CFR 1910.134. Users of respirators should also refer to the "NIOSH Guide to the Selection and Use of Particulate Respirators Certified Under 42 CFR 84" DHHS (NIOSH) Publication No. 96-101.

Additional questions have been raised about which class of respirator should be used where a particular OSHA standard requires the use of a respirator with HEPA filters. Where workers are exposed to a hazard that would require the use of a respirator with HEPA filters the appropriate class of respirator under the 42 CFR Part 84 certification would be the Type 100. NIOSH has presently designated only the P100 respirator with the magenta color coding. However, the N100, R100, or P100 respirators have been certified at the 99.97% efficiency level and are identified as HEPA respirators.

Users are cautioned to note that the respirator classes are designated for use in certain environments with the P100 being the most universal (hence NIOSH's magenta color coding). Under the new classes of respirators, if oil particles are present, users of respirators must refer to the following guide:

N series -- Not resistant to oil

R series -- Resistant to oil

P series -- oil Proof

Information from Center For Disease Control: https://www.cdc.gov/swineflu/masks.htm
When crowded settings or close contact with others cannot be avoided, the use of facemasks1 or respirators2 in areas where transmission of swine influenza A (H1N1) virus has been confirmed should be considered as follows:

Whenever possible, rather than relying on the use of facemasks or respirators, close contact with people who might be ill and being in crowded settings should be avoided.

Facemasks1 should be considered for use by individuals who enter crowded settings, both to protect their nose and mouth from other people's coughs and to reduce the wearers' likelihood of coughing on others; the time spent in crowded settings should be as short as possible.

Respirators2 should be considered for use by individuals for whom close contact with an infectious person is unavoidable. This can include selected individuals who must care for a sick person (e.g., family member with a respiratory infection) at home.

These interim recommendations will be revised as new information about the use of facemasks and respirators in the current setting becomes available.

Unless otherwise specified, "respirator" refers to an N95 or higher filtering facepiece respirator certified by the U.S. National Institute for Occupational Safety and Health (NIOSH).