On 05/07/2020, the FDA removed most of the previously authorized KN-95 masks from their approval list. Certain Filtering Facepiece Respirators from China May Not Provide Adequate Respiratory Protection – Letter to Health Care Providers

https://www.fda.gov/medical-devices/letters-health-care-providers/certain-filtering-facepiece-respirators-china-may-not-provide-adequate-respiratory-protection-letter?fbclid=IwAR0Zf7BRzf1kWJ_AUk3dzSejV6jncki8KGPPwsU83kpoX4uzohP8j3S-F3c