Which NIOSH filter model numbers are certified for CN/CS and where can their approval documents be viewed?
Executive summary
No document in the supplied reporting explicitly lists NIOSH filter model numbers certified for protection against the chemical agents CN (chloroacetophenone) or CS (o‑chloroacetophenylidene malononitrile); the authoritative source to answer that specific question is the NIOSH Certified Equipment List (CEL), which allows searches by TC approval number and by the "Protections" criteria and provides the approval documents and details for each certified respirator [1] [2]. The reporting establishes how NIOSH labels approvals (TC-84A/TC-21C formats) and makes approval records available, but does not itself enumerate CN/CS‑rated model numbers [3] [4] [1].
1. What the records actually contain and how approvals are numbered
NIOSH approvals for filtering facepiece respirators carry a testing and certification (TC) approval number—most commonly displayed in the TC‑84A‑XXXX format for disposable FFRs—and NIOSH requires those approval numbers to be printed on respirators and listed in its official records [4] [5]. Older and different device types can use other TC series (for example TC‑21C for certain powered or negative‑pressure devices), and the CEL and related NIOSH pages are the designated publication points for those approvals [3] [1].
2. Why the supplied reporting cannot directly name CN/CS‑rated models
None of the provided snippets or pages explicitly states which model numbers are certified against CN or CS agents; the sources describe the CEL, approval numbering and how to search but do not reproduce lists of chemical‑specific protection approvals or cite CN/CS protections for particular TC numbers [1] [2] [6]. Therefore, any definitive list of CN/CS‑rated model numbers must be obtained by querying the live NIOSH CEL or the specific approval record pages referenced by CEL results, information the supplied reporting points to but does not itself include [1].
3. How to find model numbers certified for CN/CS in the NIOSH records
The practical route—documented in the NIOSH CEL guidance—is to search the NIOSH Certified Equipment List using either TC approval numbers or by selecting protections in the query form; the TC field accepts multiple values and the CEL result rows link to detailed approval pages where the protection type (what the filter/cartridge is certified to protect against) and the approval holder and part/model numbers are shown [1]. NIOSH’s user guidance and CDC pages repeatedly emphasize that the CEL is the authoritative, regularly updated list of NIOSH‑approved respirators and that the approval number and protection ratings are part of that record [2] [4].
4. Where approval documents and supporting materials can be viewed
Approval details and related documentation can be accessed through the CEL result detail pages, which include the approval (TC) number and allow the user to view or download supporting documents and user instructions for that approval [1] [7]. NPPTL/NIOSH is the publisher and custodian of the CEL and the regulatory framework for approvals is 42 CFR Part 84, which governs the certification process and the information that accompanies an approval [3] [8]. For authoritative context about how approvals are issued and what they cover, the NIOSH/NPPTL pages linked from the CEL and the NIOSH fact sheets are the source documents cited by the reporting [9] [1].
5. Caveats, practical cautions, and alternative sources
Respirator approvals are manufacturer‑ and model‑specific and parts or cartridges cannot be mixed across different approved assemblies without voiding the approval, a point underscored in the reporting and relevant when matching a CN/CS‑rated cartridge to a facepiece [10]. Occupational rules such as OSHA’s respiratory protection standard reference use of NIOSH‑approved filters and the Part 84 approvals when specifying acceptable equipment for workplace protection, so workplace compliance or procurement should confirm TC approvals and application notes on the CEL detail pages [8]. Because the provided sources do not list CN/CS model numbers directly, the only verifiable method—per the cited material—is to perform targeted searches on the NIOSH CEL and open the approval detail pages for candidate TC numbers to confirm whether CN or CS is listed among the protections [1] [2].