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Based on a thorough review of OSHA respiratory protection requirements, I have found inconsistent interpretations regarding the voluntary use and need for medical clearances for filtering facepieces and dust masks. OSHA requirements as provided in 29 CFR 1910.134, respirator guidance documents, and the online OSHA Respiratory Protection eTool† are contradictory.

Based on my review of these documents, I have made the following determinations:

  • A dust mask is a filtering facepiece.
  • All filtering facepieces are not all dust masks.
  • A filtering facepiece that contains a NIOSH designation is a tight-sealing respirator.

Therefore, if an employee chooses to wear a filtering facepiece respirator (voluntarily) with a NIOSH designation s/he must be: 1) medically qualified, 2) properly trained in the facility respiratory protection program, and 3) included in a respiratory protection program. The individual, however, does not need to be fit tested.

From a practical standpoint, an employee may wear a NIOSH-designated filtering facepiece respirator when s/he is overexposed. In this circumstance, the employee obviously needs to be medically evaluated and cleared to wear the selected respirator as use may adversely affect the employee’s heart and lungs. This risk exists whether respirator use is voluntary or mandatory.

An OSHA respiratory protection specialist concurred with my interpretation and acknowledged those requirements in 29 CFR 1910.134 conflict with OSHA guidance documents and the OSHA Respiratory Protection eTool. He also stated that in cases where regulatory requirements and guidance documents differ, the requirements as stated in the statute take precedent.



Where respirator use is not required:

29 CFR 1910.134(c)(2)(i)

An employer may provide respirators at the request of employees or permit employees to use their own respirators, if the employer determines that such respirator use will not in itself create a hazard. If the employer determines that any voluntary respirator use is permissible, the employer shall provide the respirator users with the information contained in Appendix D to this section (“Information for Employees Using Respirators When Not Required Under the Standard”); and

29 CFR 1910.134(c)(2)(ii)

In addition, the employer must establish and implement those elements of a written respiratory protection program necessary to ensure that any employee using a respirator voluntarily is medically able to use that respirator, and that the respirator is cleaned, stored, and maintained so that its use does not present a health hazard to the user. Exception: Employers are not required to include in a written respiratory protection program those employees whose only use of respirators involves the voluntary use of filtering facepieces (dust masks).

Interpretation: A filtering facepiece as a dust mask is not a respirator.

29 CFR 1910.134(d)(1)(ii)

This APF category includes filtering facepieces, and half masks with elastomeric facepieces.


These are filtering facepiece half-mask respirators, sometimes referred to as N95s. A filtering facepiece respirator covers the nose and mouth, and is a tight-fitting, air-purifying respirator in which the whole facepiece functions as the filter. Filtering facepieces may or may not have an exhalation valve to help exhaled breath exit the facepiece. They need to be fit tested, unless you are wearing them under voluntary use conditions. Filtering facepiece respirators filter out particles and do not protect against non-particulate hazards such as gases or vapors.


A respirator is a protective device that covers the nose and mouth or the entire face or head to guard the wearer against hazardous atmospheres. Respirators may be:

Tight-fitting, that is, half masks, which cover the mouth and nose and full facepieces that cover the face from the hairline to below the chin; or
Loose-fitting, such as hoods or helmets that cover the head completely.
In addition, there are two major classes of respirators:
Air-purifying, which remove contaminants from the air; and
Atmosphere-supplying, which provide clean, breathable air from an uncontaminated source. As a general rule, atmosphere-supplying respirators are used for more hazardous exposures.

† Source: OSHA Respiratory Protection eTool, https://www.osha.gov/SLTC/etools/respiratory/index.html