CBRN Respirator Approval Resources

During the development of the NIOSH CBRN APR Statement of Standard in the early 2000s, NIOSH and its federal partners, including the Department of Defense (DoD), Department of Justice, and Department of Energy, conducted a hazard assessment with a goal to list all potential CBRN hazards that may pose a risk to emergency responders and are likely to be used in a disaster. This hazard assessment consisted of a comprehensive review of technical data and the evaluation of various lists of chemicals that could be used in a terrorist incident [NIOSH 2018]. Further, physical and chemical properties (including filtration mechanisms) were evaluated. The final list included 139 CBRN hazards. NIOSH then worked on developing minimum performance requirements to ensure that NIOSH-approved CBRN respirators would provide protection against these hazards [NIOSH 2018].

To do so, NIOSH further categorized the 139 hazards into seven chemical families,¹ characterized by common chemical properties and filtration behavior [NIOSH 2018]. As part of its Respirator Approval Program evaluation of APRs, APERs, and PAPRs, NIOSH used 11 of these chemicals as representatives from the seven NIOSH chemical families, referring to them as test representative agents.²

¹ NIOSH’s seven CBRN Chemical Families include Organic Vapor, Acid Gas, Base Gas, Nitrogen Oxide, Hydride, Formaldehyde, and the Particulate Family.

² NIOSH’s 11 CBRN test representative agents include cyclohexane, sulfur dioxide, hydrogen cyanide, phosgene, hydrogen sulfide, cyanogen chloride, ammonia, dioctyl phthalate, nitrogen dioxide, formaldehyde, and phosphine.

In 2018, NIOSH and its Partners Evaluated New and Emerging CBRN Hazards

NIOSH must continue to ensure that the test representative agents used to evaluate CBRN APR canisters represent current or potential hazards, which are always evolving. From 2016 – 2018, NIOSH partnered with the DoD and the Department of Homeland Security (DHS) to identify and evaluate new/emerging chemical and radiological respiratory hazards that may pose a risk to emergency responders. The project team included several individuals present during the initial 2001 hazard assessment.

NIOSH and its partners first identified and compiled hazards by reviewing various hazard assessments available to the DHS. The group then developed a four-step evaluation process to assess each hazard (Fig. 1) which included:

1. evaluating its chemical and physical properties,
2. evaluating its actual or anticipated filtration behavior within the CBRN canister (i.e., physical adsorption, chemisorption, or mechanical filtration),
3. categorizing it into one of NIOSH’s Chemical Families, and
4. comparing it against the existing test representative agents in its respective Chemical Family to determine the need for additional test agents.

Figure 1: Summary of the process NIOSH and its partners took to assess new/emerging CBRN hazards [Greenawald et al. 2020]. TRA = test representative agent.

During the hazard assessment, a total of 238 hazards (192 chemicals and 46 radiologicals) were identified [Greenawald et al. 2020]. Of the 238 hazards, 203 could be grouped into one of the existing seven NIOSH Chemical Families. A total of 35 hazards could not be initially categorized: 29 hazards were too unstable in the emergency responder operational environment (e.g., decompose quickly) and six needed further testing and evaluation to confirm their categorization into a NIOSH Chemical Family. For the six that underwent additional testing, NIOSH ultimately determined that it was appropriate to categorize these six hazards within the existing seven NIOSH Chemical Families [Greenawald et al. 2020].

NIOSH Expanded its CBRN APR Protection List – No Changes Were Needed to NIOSH’s CBRN Statements of Standard

After reviewing each of these 238 hazards, the key finding of this effort was that the current 11 CBRN test representative agents continued to represent the known CBRN hazards and should remain the basis for NIOSH respirator approval testing for respirators claiming protections against CBRN hazards. Thus, no changes were needed to NIOSH’s original 11 CBRN test representative agents or NIOSH’s CBRN APR, APER, or PAPR Statements of Standard. However, because of the described evaluation, NIOSH has expanded its original CBRN APR Protection List of 139 hazards to include those additional hazards identified—i.e., NIOSH’s CBRN APR Protection List is now comprised of a total of 286 hazards. Table 1 shows a comparison between the original and updated lists. The NIOSH CBRN test representative agents and list of hazards in each NIOSH Chemical Family, constituting NIOSH’s updated CBRN APR Protection List, is below.

Note: The updated CBRN APR Protection List supersedes the list in NIOSH’s CBRN Respiratory Protection Handbook (Report version 2018-166) and the list in NIOSH’s 2005 interim guidance for CBRN APRs [NIOSH 2005]. This Handbook is being updated.

 Table 1: Summary of the original and updated NIOSH CBRN APR Protection List. TRA=test representative agent.

³ Biologicals were not evaluated during this 2018 CBRN hazard assessment.

References

Lee A. Greenawald, Christopher J. Karwacki, Frank Palya, Matthew A. Browe, David Bradley & Jonathan V. Szalajda [2020] Conducting an evaluation of CBRN canister protection capabilities against emerging chemical and radiological hazards, Journal of Occupational and Environmental Hygiene, 17:10, 480-494, DOI: 10.1080/15459624.2020.1798452

NIOSH [2005]. NIOSH Interim Guidance on the Use of Chemical, Biological, Radiological, and Nuclear (CBRN) Full Facepiece, Air-Purifying Respirators/Gas Masks Certified Under 42 CFR Part 84.  Accessed 08/30/2021.

NIOSH [2018]. Chemical, Biological, Radiological, and Nuclear (CBRN) Respiratory Protection Handbook. By Janssen L, Johnson AT, Johnson JS, Mansdorf SZ, Medici OR, Metzler RW, Rehak TR, Szalajda JV. Pittsburgh, PA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2018-166, .

NIOSH [2019]. Respirator Standards. Accessed 08/30/2021.

NIOSH’s Updated CBRN APR Canister Protection List

As part of a NIOSH-approved CBRN APR, the CBRN canister provides protection against a minimum of 286 identified CBRN hazards, which are classified into seven chemical families: Organic Vapors (109), Acid Gases (48), Base Gases (4), Hydrides (4), Nitrogen Oxides (6), Particulates (114) [comprised of 56 chemical, 13 biological, and 45 radiological and nuclear particulate threats], and Formaldehyde (1). Actual CBRN incident responses may lead to adjustments to this canister protection listing. The service life of a CBRN canister depends upon many factors including environmental conditions (e.g., temperature, percent relative humidity), breathing rate, filtering capacity, and the type and concentration of contaminants in the air. Filtering capacity is based on many product-specific criteria. It is important that you follow the manufacturer’s guidance and consult your respiratory protection program administrator for additional guidance on determining change-out schedules.

The test representative agents used by NIOSH for approval testing are listed. Those hazards identified during the 2018 hazard assessment are designated with asterisks (*).

NIOSH Organic Vapors Family (109 hazards)

NIOSH Acid Gas Family (48 hazards)

Particulate Family Canister Protections (114 hazards)

NIOSH Hydride Family (4 hazards)

NIOSH Formaldehyde Family (1 hazard)

NIOSH Basic Gas Family (4 hazards)

NIOSH Nitrogen Oxide Family (6 hazards)

Disclaimer: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Mention of any company or product does not constitute endorsement by the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention.