Dust Mask or Respirator? Single Use Respiratory Protection at a Glance by Jim Kaznosky, Senior Environmental & Occupational Safety Specialist

In the Spring 2014 issue of SafetyMatters, EH&S introduced some occupational exposure related theory on the use of respiratory protection equipment in an article titled “Minimizing Chemical Exposures in Laboratories: A Hierarchy of Controls”  The article presented PPE as the “last line of defense” against exposure hazards and demonstrated that with the proper use of engineering controls, such as chemical fume hoods, and the employment of correct work practices, the need to use respiratory protection in a laboratory setting is minimal. There may come a time, however, when either personnel might feel more comfortable wearing some form of respiratory protection or may even be required to do so while performing a specific job task.  In this article, we focus on the differences between two commonly used types of single-use respiratory protection devices – nuisance dust masks (“dust masks”), and N-95 respirators - and the requirements for wearing such a device while working at Columbia. 

At first glance, dust masks (Fig 1) and N95 [or N99, P95, or P99 (Fig 2)] respirators look very similar, physically, but are in fact different in use and in other requirements for users.

mask mask
Fig 1 Fig 2

 A dust mask is typically worn for activities during which nuisance dust may be generated, thus its use should be limited to non-hazardous environments.  It is meant for single use and offers a general protective barrier between the user and the environment.  No fit testing or notification to EH&S is required prior to use.  The user should be aware of the general hazards in the environment they plan on working in to ensure the dust mask is appropriate for use.

Dust masks are often confused or incorrectly considered synonymous with N95-rated single use respirators (aka filtering face piece respirators). These respirators are differentiated from dust masks by a NIOSH approval rating stamped on the mask certifying a filtration efficiency of at least 95% against solid and liquid particles tested using NIOSH criteria. 

The NIOSH certification distinguishes the nuisance dust mask from the N95 respirator.   This is a critical factor, in that the use of an N95 respirator activates a host of OSHA requirements to be met by the user and the employer, including:

  • undergoing medical surveillance to ensure the user is medically qualified to wear the respirator;
  • training the user in the respirator’s use and limitations of use:
  • fit-testing the user to the specific respirator to be used; and, 
  • having a risk assessment, performed by EH&S prior to the above, to determine if there are other hazard controls that can effectively reduce the hazard before the use of PPE is warranted. Again, PPE is the last choice for minimizing workplace hazards, particularly as it relates to respirator use for minimizing inhalation hazards.

It is important to note that N95 respirators may also be voluntarily worn, but only if no actual hazard exists that requires use of a respirator.  Additionally, the use of the respirator should not produce any additional hazard to the user. 
More information on respirator use at Columbia University is available on the Respiratory Protection Program webpage @ http://ehs.columbia.edu/RespiratoryProtectionProgram.html.

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