Soon after healthcare workers began warning of personal protective equipment (PPE) shortages, companies and other organizations started claiming their decontamination systems could reprocess used filtering facepiece respirators (FFRs) such as N95s up to 20 times.

The FDA began issuing emergency use authorizations (EUAs) for FFR decontamination systems with a range of allowable cycles and major media organizations and nurses began to question the claims about the number of times an FFR could be safely decontaminated and reused. Companies, universities and other organizations gained EUAs for sterilizing masks up to 10 times (Sterilucent and Steris), and Stryker (up to two times), with a total of 13 organizations now holding 15 such EUAs.

Today, the FDA announced that it has reissued EUAs for nine of those decontamination systems to reprocess each compatible N95 respirator up to four times only. Renewed EUAs went to Advanced Sterilization Products, Battelle, Duke University, Michigan State University, Sterilucent, Steris (two EUAs), Stryker (two EUAs), and Technical Safety Services.

“Based on the FDA’s review of real-world use of these systems and evidence from adverse events and scientific literature, including studies regarding N95 respirator failures from simulated and real-world use, the FDA has determined that it is appropriate to protect the public health or safety to revise certain decontamination system EUAs to limit the number of decontamination cycles and respirator reuses permitted under each authorization,” the agency said in a news release. “Specifically, the reissued EUAs for certain decontamination systems are now only authorized to decontaminate each compatible N95 respirator a maximum of four or fewer times.”

Nearly 3,000 U.S. healthcare workers have died from the virus since the pandemic struck in China in 2019, according to Kaiser Health News. The U.S. Centers for Disease Control and Prevention recommends that decontaminated respirators should only be used when new, FDA-cleared N95 respirators, NIOSH-approved N95 respirators, or other FDA-authorized respirators are not available.