Guidance for Decontamination and Reuse of N95 Filtering Facepiece Respirators (This AFL supersedes guidance provided in AFL 20-36)

Please note that this information has been superseded by a more recent item and is only retained here for reference.

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AFL 20-36.1 From the California Department of Public Health

April 11, 2020

TO: General Acute Care Hospitals

SUBJECT: Guidance for Decontamination and Reuse of N95 Filtering Facepiece Respirators (This AFL supersedes guidance provided in AFL 20-36)

All Facilities Letter (AFL) Summary

  • This AFL provides guidance for the handling of used N95 filtering facepiece respirators so they can be decontaminated and reused as respirator supplies are depleted during the Coronavirus Disease 2019 (COVID-19) pandemic.
  • This AFL revises the instructions on how to collect the used N95 filtering facepiece respirators.


The federal Centers for Disease Control and Prevention (CDC) released guidance on the decontamination and reuse of N95 filtering facepiece respirators as a crisis capacity strategy on March 31, 2020. Although there are currently no manufacturer authorized methods for filtering facepiece respirators decontamination prior to reuse, Battelle CCDS Critical Care Decontamination SystemTM, a vapor phase hydrogen peroxide (H2O2) (VPHP) system, received emergency use authorization (EUA) from the federal Food and Drug Administration (FDA) on March 29, 2020 for decontamination of N95 respirators. Facilities should continue to monitor the FDA website to determine if other EUAs have been issued.

The National Institute of Occupational Safety and Health (NIOSH) and other researchers have investigated the impact of various decontamination methods on filtration efficiency, facepiece fit, and the ability to reduce viable virus or bacteria on the respirator surface. VPHP, in addition to ultraviolet germicidal irradiation (UVGI), and moist heat, showed the most promise as potential methods to decontaminate filtering facepiece respirators.

The State of California is working with Battelle Memorial Institute to deploy their FDA emergency use authorized decontamination systems in California. Hospitals regularly use VPHP for decontamination to inactivate highly resistant pathogens, including bacterial spores and viruses for terminal decontamination of hospital rooms, biosafety cabinets, and medical equipment and materials that are intolerant to heat or have diffusion-restricted space. A number of studies (Battelle 2016, 2020; Bergman 2010, Viscusi 2009) have demonstrated that certain N95 respirators can be safely decontaminated with proper use of VPHP.

The California Department of Public Health (CDPH) will provide additional guidance on the specifics of how the State plans to transport, decontaminate, and reissue used N95 respirators. Below is guidance for how to preserve used N95 respirators now in order for them to be decontaminated in the very near future.

Even if your hospital does not plan to reuse N95 respirators, we would recommend you collect used N95 respirators so that the State can decontaminate the respirators and allocate them to areas who have a need for such a resource.

On-Site Collection

1.    Your hospital should create a N95 respirator collection station at the point of generation (i.e. hospital floor/unit).

  • Any N95 or N95-equivalent respirator that does not contain cellulose-based materials is compatible with the Battelle Decontamination System.
  • All compatible N95 respirators must be free of any visual soiling or contamination (e.g. blood, bodily fluids, makeup).
  • Compatible N95 respirators that are visually soiled or damaged should not be collected for decontamination and will be disposed of and not returned after decontamination.

2.    Each station should have a bag provided by the hospital to collect compatible N95 respirators.

  • Bags are for compatible N95 respirators only. Do not put other personal protective equipment (such as gloves), paper towels, or waste in the collection bag.

3.    With a permanent marker, each compatible N95 respirator should be labeled with a three-digit site code and a 2-digit location identifier (as shown below). The three-digit site code can be found on the Battelle Hospital List. Your organization may designate the location identifier to correspond to a specific location/floor/unit within your site.  

Site Code IDSite Location ID
                  (Assigned by Battelle POC)        (Assigned by Hospital)                                

Preparation for Shipment or Pick-up:

1.    Bags containing the contaminated compatible N95 respirators to be decontaminated (“primary collection bag”) should be closed.

2.    Place the primary collection bag into another bag (“secondary collection bag”) (provided by the hospital), which is then closed.

3.    Decontaminate the secondary collection bag with alcohol or other suitable decontaminant.

4.    Place the decontaminated bags into a rigid, closed box (supplied by the hospital) clearly labeled with a biohazard symbol, and tape the box securely shut.

5.    Label the outside of the box with the 3-digit site code and 2-digit location identifier.

Reuse Information
Following decontamination, each hospital will be provided the decontaminated N95 respiratorsthey submitted. Each hospital should inspect each returned decontaminated N95 respirator for visible damage or soiling. If visually damaged or soiled, decontaminated N95 respirators should be discarded and not reused. 

Additionally, staff should be reminded of the following:

  • Clean hands with soap and water or an alcohol-based hand sanitizer before and after touching or adjusting the N95 respirator.
  • Avoid touching the inside of the N95 respirator.
  • Use a pair of clean (non-sterile) gloves when donning and performing a user seal check.
  • Visually inspect the N95 respirator to determine if its integrity has been compromised.
  • Check that components such as the straps, nose bridge, and nose foam material did not degrade, which can affect the quality of the fit, and seal.
  • If the integrity of any part of the N95 respirator is compromised, or if a successful user seal check cannot be performed, discard the N95 respirator.

Battelle Memorial Institute has developed a fact sheet for health care providers who use the decontaminated N95 respirators.

If you have any questions about infection prevention and control of COVID-19, please contact the CDPH Healthcare-Associated Infections Program via email at or


Original signed by Heidi W. Steinecker

Heidi W. Steinecker
Deputy Director