The Food and Drug Administration has revised its guidance on respirators, labeling more as inappropriate for decontamination and reuse during the pandemic.

Respirators manufactured in China vary in design and performance, the agency announced Sunday, citing tests performed by the National Institute for Occupational Safety and Health. “As such, the FDA has determined that the available information does not support the decontamination of these respirators.”

No longer are non-NIOSH-approved disposable filtering facepiece respirators manufactured in China approved for cleaning and reuse. Nor are certain respirators that have exhalation valves.

Decontamination systems are now only authorized to decontaminate non-cellulose compatible N95 respirators. “Healthcare personnel should not reuse a respirator that is incompatible with an authorized decontamination system but has nonetheless been decontaminated,” the agency concluded.

The full guidance with links to authorized brands can be found on the FDA’s website.