According to 3M—the country's leading producer of N95 mask respirators—over 10 million fake versions of it's coveted masks have been seized in the U.S. since the start of the pandemic last year. Even big name hospitals like the Cleveland Clinic have fallen prey to the counterfeit masks.

Now the Centers for Disease Control and Prevention’s National Institute for Occupational Safety and Health (NIOSH) has provided guidance on how to identify fake N95 masks.

According to NIOSH, here are seven signs of counterfeit respirators that physicians and staffers at medical groups and health systems should look for:

• No markings at all on the filtering facepiece respirator.
• No approval number on filtering facepiece respirator or headband.
• No NIOSH markings.
• NIOSH spelled incorrectly.
• Presence of decorative fabric or other decorative add-ons.
• Claims of approval for children—NIOSH does not approve any type of respiratory protection for children.
• Filtering facepiece respirator has ear loops instead of headbands

A NIOSH-approved mask will feature these markings on the exterior of respirator:

• Approval number.
• Brand name, registered trademark or easily understood abbreviation.
• NIOSH name in block letters, or NIOSH logo.
• Filter class (N, P or R) and filter efficiency level (95, 99 or 100).
• Lot number—recommended, but not required.
• Model number.

Learn more about how to spot counterfeit respirators at the NIOSH National Personal Protective Technology Laboratory, which features a listing—with pictures—of masks that are wrongly being marketed as having NIOSH approval.

Meanwhile, NIOSH maintains a list of approved filtering facepiece respirators by class and filtration level, with contact information for the manufacturers.