Breathing hazards such as dust, fumes, mist, vapors, and gases exist in many workplaces. Respirators are used when these hazards cannot be fully managed by engineering and administrative controls or other safety measures. Understanding the differences between common surgical masks and the types of respirators regulated by the Occupational Safety and Health Administration (OSHA) helps keep workers protected and workplaces compliant.
Surgical Masks, N95s, and KN95s: What’s the Difference?
Surgical masks are loose-fitting and mainly provide a physical barrier to protect the wearer from large droplets such as those generated from a splash or splatter. They do not seal tightly against the user’s face and are not designed for protection from airborne contaminants. Surgical masks are not covered by OSHA’s Respiratory Protection Standard [29 CFR 1910.134].
N95 respirators are tight-fitting and designed to protect the wearer from particulates, but not gases or vapors. When properly worn, they filter at least 95% of small airborne particulates and must seal to the face properly to function effectively. Use of these disposable, filtering facepiece respirators is regulated by OSHA as discussed below.
KN95 respirators are also designed to have a minimum particulate filtration efficiency of 95%. However, they follow a Chinese manufacturing standard (GB 2626-2019), not the U.S. National Institute for Occupational Safety and Health (NIOSH) certification used for N95s. Because of this, fit and quality can vary, and generally KN95s are prohibited for mandatory respirator use in U.S. workplaces.
N95 Respirators and OSHA Requirements
As noted above, N95 respirators are often used when workers may be exposed to harmful airborne particulates and other controls (e.g., engineering, administrative) are not sufficient. When an employer requires N95 use, OSHA’s Respiratory Protection Standard applies.
At a high level, mandatory N95 use must be supported by a written respiratory protection program that includes requirements for training, medical clearance, and fit testing to ensure workers can safely wear a respirator and that it fits properly. These elements are essential—without them, an N95 may not provide the protection it is intended to deliver.
It should be noted that voluntary use of N95s in the workplace does not trigger these requirements. However, users must read and sign Appendix D of the Respiratory Protection Standard to ensure they know how to wear them properly and avoid hazards arising from improper use.
Other Types of Respirators and What They Protect Against
As we’ve discussed, N95 respirators protect against particulates only. Other types of respirators are used for different hazards and provide varying levels of protection as outlined below:
- Half‑facepiece elastomeric respirators protect against particulates, fumes, mists, gases, and vapors when the correct filter and/or cartridge is selected for the specific chemical. They form a tight seal over the wearer’s nose and mouth.
- Full‑facepiece elastomeric respirators remove atmospheric contaminants including particulates, fumes, mists, gases, and vapors when paired with the proper cartridges and/or filters. They provide full facial coverage and offer a higher level of protection than half-facepiece respirators as they form a seal around the entire perimeter of the face rather than just the nose and mouth, reducing the risk of leakage.
- Powered air‑purifying respirators (PAPRs) are effective against exposure to particulates, gases, and vapors using appropriate filters or cartridges. Because they provide a positive pressure environment inside the mask, they make breathing easier than with other respirator types. PAPRs use a battery-operated blower to provide the user with clean air through a loose-fitting hood, a tight-fitting respirator, or a helmet.
- Supplied‑air respirators (SARs), such as self-contained breathing apparatus (SCBAs), provide clean air from a separate source and are used in oxygen-deficient environments, areas with unknown contaminant concentrations, or those that are considered immediately dangerous to life and health (IDLH).
Final Takeaway
Respiratory protection is not just about wearing a mask. The right respirator must be selected for the hazard(s) present, and when their use is required, they must fit properly and be supported by training and medical evaluation. When N95s are required in the workplace, OSHA rules apply as they do with all other types of respirators—and following them is critical to protect workers’ health and maintain compliance.
OSHA continues to review and update respiratory protection requirements. In a July 1, 2025 Federal Register notice [90 FR 28463], the Agency proposed amendments to the medical evaluation requirements for certain types of respirators, including N95s. Additional information can be found in our OSHA Respiratory Protection Standard: Updates on Proposed Amendments blog.
If you need assistance selecting the right type of respirator, determining whether the OSHA Respiratory Protection Standard applies to you or your employees, or help implementing a respiratory protection program at your facility, contact us!
This blog was written by Tianyi Huang, PhD, a Consulting Safety Officer at Safety Partners.
