Half-mask respirator
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OSHA approves two protocols for respirator fit testing

September 25, 2019

Washington — OSHA has issued a final rule that adds two fit testing protocols to the agency’s respiratory protection standard (1910.134).

According to a Sept. 25 press release, the additions are:

  • The modified ambient aerosol condensation nuclei counter quantitative fit testing protocol for full-facepiece and half-mask elastomeric respirators
  • The modified ambient aerosol CNC quantitative fit testing protocol for filtering facepiece respirators

These new methods are in addition to the standard’s four existing protocols and are variations of OSHA’s original ambient aerosol CNC protocol, but have fewer test exercises, shorter exercise duration and a more streamlined sampling sequence, the release states.


OSHA claims the amended rule will not impose extra costs on employers and will not require those in general industries, shipyard employment and construction to update or replace any current fit testing methods.

The amended final rule is scheduled to be published in the Sept. 26 Federal Register.