Most KN95 Masks Imported From China Fail to Meet US Standards

Megan Brooks

September 22, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Up to 70% of KN95 masks, which are certified in China but not by the US National Institute for Occupational Safety and Health (NIOSH),, do not meet US standards for effectiveness, the nonprofit patient safety organization ECRI warned today in a high-priority hazard alert.

"Because of the dire situation, US hospitals bought hundreds of thousands of masks produced in China over the past six months, and we're finding that many aren't safe and effective against the spread of COVID-19," Marcus Schabacker, MD, PhD, ECRI president and CEO, said in a statement.

ECRI quality assurance researchers rigorously tested nearly 200 KN95-style masks, reflecting 15 different manufacturer models purchased by some of the largest health systems in the United States.

They found that for 60% to 70% of the imported masks that had not been certified by the US National Institute for Occupational Safety and Health (NIOSH), filtration performance was "significantly inferior" to NIOSH-certified N95s. These masks did not filter 95% of aerosol particulates, contrary to what their name suggests.

"Using masks that don't meet US standards puts patients and frontline healthcare workers at risk of infection. As ECRI research shows, we strongly recommend that healthcare providers going forward do more due diligence before purchasing masks that aren't made or certified in America," Schabacker said.

According to ECRI, US domestic production capacity for N95s has increased significantly, but there remain widespread limits on quantities that can be purchased.

The organization says KN95s or other non-NIOSH-certified masks should only be used as a "last resort" when treating COVID-19 patients and only when NIOSH-certified N95s or other respirators offering comparable or better protection are not available.

"KN95 masks that don't meet US regulatory standards still generally provide more respiratory protection than surgical or cloth masks and can be used in certain clinical settings," Michael Argentieri, ECRI vice president for technology and safety, said in the statement.

Editor's note: This article has been updated to clarify the difference between an N95 and KN95 mask.

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