Health care workers on the front lines of patient care are at increased risk of exposure to SARS-CoV-2, the novel coronavirus that causes COVID-19. The Centers for Disease Control and Prevention (CDC) and the Occupational Safety and Health Administration require respiratory protection for staff who are caring for patients with suspected or confirmed infectious disease. However, the limited availability of filtering facepiece respirators (FFRs) and other personal protective equipment (PPE) has made it necessary for the CDC to create strategies for extended use and reuse of FFRs during the COVID-19 pandemic. Such strategies (without decontamination of the respirator) are available from the CDC’s National Institute for Occupational Safety and Health (NIOSH).

Decontamination methods have been approved by the Food and Drug Administration (FDA), and the CDC has provided Crisis Standards of Care Decontamination Recommendations that include FFR decontamination strategies. The purpose of effective FFR decontamination is to reduce the pathogen burden while maintaining the functionality of the FFR without residual chemical hazard. The CDC recommends that the decontamination methods selected should also include evaluation of the respirator’s ability to maintain filtration performance, characteristics of fit remains similar to pre-decontamination, and the continued safety of the FFR for the wearer as achieved by inactivating a threat such as SARS-CoV2.

At present, FFRs are considered one-time use and there are no manufacturer-authorized methods for decontaminating FFRs for reuse. Disposable FFRs are not approved for routine decontamination and reuse as standard of care; it should only be practiced as a crisis capacity strategy.

The filter media in NIOSH-approved respirators varies by manufacturer and must be considered when evaluating decontamination methods. The ability of the respirator filter media to withstand cleaning and disinfection techniques is not a NIOSH performance requirement. Furthermore, there is currently no data supporting the effectiveness of FFR decontamination methods specifically against SARS-CoV-2.

Sterilization of single-use devices such as PPE is not a standard practice, so guidance is limited. The CDC recommends that the respirator’s manufacturer should be consulted about the impact on its specific respirator of any decontamination method being considered. Once the manufacturer or a third party has confirmed that respirators can be successfully decontaminated without affecting their performance, FFRs decontaminated following those recommendations can be worn for any patient care activities, with careful consideration regarding aerosol-generating procedures.

Other pathogens may also be present on FFRs and limited data is available about the effect of decontamination methods on such pathogens. Further work is needed to ensure that SARS-CoV-2 and other pathogens are inactivated by decontamination. Therefore, FFRs should be handled carefully even after decontamination.

Current methods of FFR decontamination include:

  • Ultraviolet germicidal irradiation (UVGI)
  • Vaporous hydrogen peroxide (VHP)
  • Moist heat
  • Steam treatment
  • Liquid hydrogen peroxide
  • Autoclave, dry heat, isopropyl alcohol, soap, dry microwave irradiation and bleach disinfectant wipes
  • Ethylene oxide

Another decontamination method that may be feasible using equipment on hand is photodynamic inactivation of pathogens using methylene blue plus visible light exposure. These methods and their effectiveness are reviewed in Table 1.

According to the CDC, UVGI, VHP, and moist heat showed the most promise as potential methods for decontaminating FFRs. It is recommended that researchers, decontamination companies, health care systems and individual hospitals continue to focus efforts on these technologies and the effectiveness of the respirator, including its performance, filtration and device fit.

This guide is intended to help Vizient® members make informed decisions when considering decontamination methods by providing a concise review of currently available options and their associated hazards. The CDC provides a summary of decontamination methods tested on various FFR models in Table 4 on its Decontamination and Reuse of Filtering Facepiece Respirators webpage. Table 2 below provides a summary of current regulatory guidance.

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Table 1. Summary of decontamination methods

Method Documented effectiveness
Ultraviolet germicidal irradiation

Disinfection efficacy is dependent upon dose. Not all UV lamps provide the same intensity so treatment times must be adjusted accordingly.

Vaporous hydrogen peroxide

Evidence of minimal effect on filtration and fit; 99.9999% efficiency in killing bacterial spores.

Moist heat

Causes minimal degradation in filtration and fit performance; the major limitation is the uncertainty about disinfection efficacy for various pathogens.

Steam treatment

Not all microwaves are constructed the same and some are more powerful than others; the effect of higher-powered microwaves on FFRs is unknown. Metal nosebands on FFRs may cause arcing (sparks inside the microwave oven) during exposure to microwaves.

Liquid hydrogen peroxide

No effect on FFR filtration performance; FFR fit and disinfection efficacy not assessed.

Autoclave, dry heat, isopropyl alcohol, soap, dry microwave irradiation, bleach, disinfectant wipes

Autoclaving and the use of disinfectant wipes are not recommended. Decontamination using an autoclave, 160°C dry heat, 70% isopropyl alcohol, microwave irradiation and soap and water caused significant filter degradation of both FFRs and particle penetration levels. Decontamination with bleach caused slight degradation in filtration performance and created an odor that would make the FFR unsuitable for use. One type of wipe caused a sample of FFRs to exceed 5% penetration.

Ethylene oxide

Not recommended as a crisis strategy as it may be harmful to the wearer.

Other methods not tested Other decontamination capabilities such as photodynamic inactivation of pathogens using methylene blue plus visible light exposure may be feasible, but there is no current data to evaluate their effect on FFR filtration and fit.

Table 2. Regulatory guidance

Agency or
organization
Recommendation Additional comments
FDA

The FDA has approved a decontamination process for N95 face masks:

The FDA’s recommendations are intended to supplement, not replace, specific controls and procedures developed by health care organizations, the CDC, or the CDC’s HICPAC to aid in infection prevention and control. EUA allowance has been granted to Advanced Sterilization Products (ASP) STERRAD sterilization, STERIS sterilization and steam decontamination cycles, Stryker STERIZONE and Stryker Sustainability Solutions VHP N95 Respirator Decontamination System, Sterilucent HC 80TT Vaporized Hydrogen Peroxide Sterilizer, and Battelle, Duke, Michigan State and Technical Safety Services 20-CS Decontamination Systems for FFR decontamination.
CDC and NIOSH

CDC and NIOSH do not recommend that FFRs be decontaminated and reused as standard care. This practice would be inconsistent with their approved use, but it is understood that in times of crisis, this option may need to be considered during FFR shortages.

UVGI, VHP and moist heat showed the most promise as potential methods to decontaminate FFRs. Researchers, decontamination companies, health care systems and individual hospitals should focus efforts on these technologies.
AORN

Reuse of N95 respirators is not safe nor commensurate with standards of care and should only be considered in a crisis situation when other strategizes to optimize respirator use have failed.

A maximum number of safe reuses cannot be stated because safe reuse is dependent on contamination over time. Use of a cleanable face shield over the N95 is preferred over a surgical mask to reduce surface contamination.

The Joint Commission

Disinfecting or reprocessing disposable respirators (and face masks) is not recommended because the integrity of the respirator may be compromised.

Examples of disinfecting or reprocessing that are not recommended include:
  • Washing face masks or respirators with soap and water
  • Spraying face masks or respirators with disinfectant after use
  • High-level disinfection of face masks or respirators
  • Sterilizing face masks or respirators
OSHA

Interim guidance only for enforcing the Respiratory Protection standard, 29 CFR § 1910.134: Discretion to permit the extended use and reuse of respirators, as well as the use of respirators that are beyond their manufacturer’s recommended shelf life.

Enforcement Guidance for Respiratory Protection and the N95 Shortage Due to the Coronavirus Disease 2019 (COVID-19) Pandemic

Abbreviations: AORN = Association of Perioperative Registered Nurses; CDC = Centers for Disease Control and Prevention; FDA = Food and Drug Administration; FFR = filtered facepiece respirator; HICPAC = Healthcare Infection Control Practices Advisory Committee; NIOSH = National Institute for Occupational Safety and Health; OSHA = Occupational Safety and Health Administration; UVGI = ultraviolet germicidal irradiation; VHP = vaporous hydrogen peroxide.

As of June 11, 2020, the FDA defines compatible N95 respirators as those that are non-cellulose containing respirators that do not have an exhalation valve that are either authorized in the NIOSH-Approved Air Purifying Respirators EUA or is authorized and identified by the FDA’s EUA as an imported, Non-NIOSH approved disposable filtering facepiece respirator.

Table 3. Abridged description of FDA EUA decontamination methods

EUA reprocessing
medical device
Process Maximum
decontamination
cycles
Location
capability
Decontaminated
product
Sterilizer
Advanced Sterilization Products (ASP) STERRAD Sterilization System Vapor Hydrogen Peroxide Up to 2 Facility based Compatible N95 or N95-equivalent respirators STERRAD 100S Cycle

STERRAD NX Standard Cycle

STERRAD 100NX Express Cycle
STERIS Sterilization Systems for Decontamination of N95 Respirators Low Temperature Sterilization System Up to 10 Facility based N95 or N95-equivalent Respirators Non-Lumen Cycle of the V-PRO® 1 Plus, maX, maX 2, V-PRO 60, and V-PRO s2
STERIS STEAM Decontamination Cycle in Cycle AMSCO Medium Steam Sterilizers Moist Heat Sterilization Up to 10 Facility based Compatible N95 respirators (3M 1860, 3M 1860S, and 3M 1804 NIOSH- approved N95 respirators) AMSCO Century Medium Steam Sterilizers 26” x 37.5” (x 36”, 48”, or 60”) and the AMSCO 400 Series Medium Steam Sterilizer Models 36H, 48H, 60H, 36SL, 48SL, 60SL, 36CH, 48CH, 60CH, 36CSL, 48CSL, 60CSL
Battelle Decontamination System* Vapor Phase Hydrogen Peroxide (VPHP) Up to 20 Current Operational Sites with plans for increasing coverage. Compatible N95 Respirators; respirators must be certified by NIOSH as an N95 Battelle CCDS Critical Care Decontamination System™ Services
Sterilucent HC 80TT Vaporized Hydrogen Peroxide Sterilizer Vapor Hydrogen Peroxide Up to 10 Facility based N95 or N95-equivalent respirators Sterilucent N95 Respirator Decontamination Cycle (“Flexible” Pre-Programmed Sterilization Cycle)
Stryker STERIZONE VP4 Sterilizer for N95 Respirator Decontamination Vapor Hydrogen Peroxide Up to 2 Facility based N95 or N95-equivalent respirators STERIZONE VP4 Respirator Decontamination Cycle
Stryker Sustainability Solutions VHP N95 Respirator Decontamination System  Vapor Hydrogen Peroxide Up to 3 Current operational site: Phoenix, AZ Compatible N95 respirators STERIS VHP 1000ED Mobile biodecontamination system utilizing a VHP sterilant within either a 200 ft2 chamber or a 546 ft2
Duke Decontamination System Vapor Phase Hydrogen Peroxide Up to 10 Current Operational Site: Duke University Health System Compatible N95 Respirators or N95-equivalent respirators Combination of Bioquell VHP systems, Drager X-am 5100, and PortaSens II/PortaSens III hydrogen peroxide monitoring equipment, and five rooms within the Duke University Health System
Technical Safety Services (TSS) 20-CS Decontamination System Vapor Hydrogen Peroxide Up to 20 Location approved by Technical Safety Services and the healthcare facility owner as appropriate for use Compatible N95 respirators Minimum clearance of 20 ft. from any access/egress doors and any/all air intakes or potential breathing zones. The 20-CS will require an overall footprint of 26 ft. by 13 ft.
Michigan State University Decontamination System Vapor Hydrogen Peroxide Up to 3 Current Operational Site: Michigan State University System Facility Compatible N95 respirators Halosil VHP system, including the HaloFogger FLX machine with HaloMist fluid

* Battelle CCDS Critical Care Decontamination System™ Services Now Available at No Charge

Decontamination systems for compatible N95 respirators