The warning to health care providers comes after additional filtration performance testing conducted by NIOSH amid the COVID-19 pandemic. 

The U.S. Food and Drug Administration (FDA) released a letter warning health care providers that certain filtering facepiece respirators from China—ie, NK95 masks—may not provide consistent and adequate respiratory protection from COVID-19. 

The warning comes after additional filtration performance testing conducted by the National Institute for Occupational Safety and Health (NIOSH) – National Personal Protective Technology Laboratory (NPPTL) of the Centers for Disease Control and Prevention (CDC).

As of May 7, and as a result of the NIOSH testing, the FDA has revised and reissued its April 3, 2020 EUA (Emergency Use Authorization)

The reissued EUA for Non-NIOSH Approved Disposable Filtering Facepiece Respiratory Manufactured in China revises one of the eligibility criteria, specifically the criterion for authorization of respirators based on review of test reports from recognized independent test laboratories submitted to the FDA by the manufacturer or importer. Thus, the reissued EUA removed from Appendix A the respirators that had been authorized under that criterion, regardless of whether they passed or failed the NIOSH testing. 

The CDC NPPTL has also released the International Assessment Results—not NIOSH—approved respirators. NPPTL points out that most of the products on the list have an ear loop design. NIOSH-approved N95s typically have head bands. The ear loop design can make it difficult to ensure that a proper fit is achieved. 

The FDA said it is taking this public health action “because a number of these respirators failed to demonstrate a minimum particulate filtration efficiency of 95% in testing conducted at NIOSH.” 

Respirators that were removed from Appendix A of the EUA and that did not meet their labeled performance standard are no longer eligible and are no longer authorized to be marketed or distributed in the United States as respirators. According to the FDA, they may be re-labeled as face masks and authorized if certain criteria are met under the Face Mask umbrella EUA .

Non-NIOSH-approved respirators that meet the other eligibility criteria in the reissued Emergency Use Authorization remain authorized by the FDA for use during the COVID-19 pandemic and continue to be listed in Appendix A.

The FDA is calling on health care facilities with these respirators in inventory to review the agency’s guidance. This information is specific to respirators that are designed to achieve a very close facial fit and to filter airborne particles. These considerations are not applicable to surgical masks or face masks that are loose-fitting and create a physical barrier between the health care personnel’s mouth and nose and potential contaminants in the immediate environment. 

Respirators no longer listed in Appendix A may not reliably provide a minimum percent particulate filtration efficiency of 95%. Respirators tested by NIOSH that failed to demonstrate a Minimum Particulate Filtration Efficiency of 95% may be considered for use as face masks for source control, to help slow the spread of infection when a person speaks, coughs, or sneezes. The FDA cautions that health care facilities should be aware that this use of face masks is different from personal protective equipment for health care personnel. 

The FDA further states that health care facilities with these respirators that have failed the NIOSH testing may wish to consider a number of factors in deciding to use these products as face masks, including current need, inventory, facility practices, and acceptable uses. The FDA also believes that respirators that no longer appear in Appendix A may not be reliably decontaminated in an decontamination system authorized for use during the COVID-19 pandemic. 

NIOSH regularly updates its list of testing results.