After the coronavirus pandemic triggered domestic shortages, officials have been forced to purchase supplies from unknown suppliers, often at higher than normal prices.
National Institute for Occupational Safety and Health, or Niosh, has stepped up procedures to ensure masks are properly certified.
Niosh tested the filtration levels of 67 imported mask types. About 60% failed N-95 standards. Most of the failed masks used ear loops to secure the mask to the head. Niosh-certified masks use elastic straps to ensure a tighter fit.
MIT professor Gregory Rutlege conducted similar tests and found that 2/3 of the masks failed Niosh standards.
Some of the failed masks were distributed by vendors that had been certified by Niosh.