April 9, 2020

NIOSH Study of Stockpiled Respirators May Inform Decisions to Release Expired N95s

Faced with a shortage of respiratory protective devices during the response to the COVID-19 pandemic, the United States government is considering whether to release N95 filtering facepiece respirators that have exceeded their manufacturer-designated shelf life from some U.S. stockpiles. Information from a NIOSH study to evaluate stockpiled N95s from 10 geographically dispersed facilities with varying storage conditions may be used to inform decisions related to product release. A report published on March 25 by NIOSH’s National Personal Protective Technology Laboratory (NPPTL) details the results of the agency’s evaluation of storage conditions and performance of stockpiled air-purifying respirators (APRs) stored in facilities across the United States. NIOSH researchers examined the inhalation and exhalation resistance and filtration performance of 3,971 APRs including 11 N95 models and one P95, all manufactured between 2003 and 2013.

NIOSH’s report states that 98 percent of the APRs tested from the stockpile facilities maintained their inhalation and exhalation resistance and filtration performance in accordance with the agency’s performance standards. According to NIOSH, all respirators that had a designated shelf life were past their shelf lives at the time of testing. Although the agency does not require approval holders to designate a shelf life, some choose to do so.

“Although the general trend observed in this study is that the majority of respirators evaluated would be protective across a variety of storage conditions, important variability was observed,” NIOSH’s report advises. “For example, respirator units sampled from select production lots of a particular model demonstrated the ability to be protective while units from a different lot of the same model, stored in the same facility, are shown to not be protective.”

NIOSH also found that select models were demonstrated to be protective when sampled from one facility but not from another with similar conditions and storage time.

NIOSH stresses that it “does not have enough information to definitively know the level of protection that may be provided by all respirators” that are stored for prolonged time periods; are stored under various conditions; or have exceeded their designated shelf life. N95s that are past their manufacturer-designated shelf life are no longer considered NIOSH-approved, but the agency notes that certain N95 models can be considered for use during this time of increased demand and decreased supply. A list of models tested in NIOSH’s study that continued to perform in accordance with the agency’s performance standards is available on page 23 of the report (PDF) and on CDC’s website.

NIOSH recommends that N95s that have exceeded their manufacturer-designated shelf life should be used only as outlined in CDC’s strategies for optimizing the supply of N95 respirators. CDC stresses that expired respirators might not perform to the requirements for which they were certified. For example, a respirator’s strap and material may degrade over time, potentially affecting the quality of the fit and seal.

“Use of expired respirators could be prioritized for situations where [healthcare personnel] are NOT exposed to pathogens, such as training and fit testing,” CDC’s website states. “As expired respirators can still serve an important purpose, healthcare facilities should retain and reserve all N95 respirators during the pandemic.”

NIOSH warns users who are provided these products to avoid a false sense of confidence, as “these devices may not provide the same level of protection as those that have not exceeded the designated shelf life.”

View NIOSH’s full report as a PDF. More information about NPPTL’s respirator assessments to support the COVID-19 response is available on the NIOSH website.