This section below summarizes evidence on the handling and storage of N95 masks.

Scientific Evidence

• The US Centers for Disease Control and Prevention (CDC), World Health Organization, and Public Health England recommend procedures at the organizational level such as appropriate documentation and recording of re-use or reprocessing, quality assurance of reprocessing measures, suitable reprocessing and storage facilities and systems, and staff training regarding safe use and donning or doffing of masks or respirators if re-use or extended use.
  • Considerations for short-term storage:
    • Inspect used mask(s) for visible soiling, saturation, or loss of structural integrity; discard masks that do not meet the inspection standards in a separate receptacle using standard institutional procedures followed by safely doffing of gloves and hand-hygiene.
    • Collect used masks for transport to processing in clearly labeled plastic bins that can be disinfected or double-bagged biohazard bags; gently remove from bags and do not compress to prevent aerosolization of contents.
    • Storage for reuse involves following one day of use with four day “quarantine” period in labelled breathable sealed container before re-use.5 Masks in three to four-day rotation should be kept at room temperature (21 to 23 Celsius) and 40% humidity.
  • Long-term storage: None of the identified sources provided information on long-term storage of used masks.

International Scan

• If reuse of N95 respirators is permitted, the CDC advises to:
  • Discard N95 respirators: 1) after use in aerosol generating procedures; 2) when they are contaminated with blood, respiratory or nasal secretions, or other bodily fluids from patients; or 3) after close contact with any patient co-infected with an infectious disease requiring contact precautions.
  • Hang used respirators in a designated storage area or keep them in a clean, breathable container such as a paper bag between uses. To minimize potential cross-contamination, store respirators so that they do not touch each other and the person using the respirator is clearly identified. Storage containers should be disposed of or cleaned regularly.
• Considerations regarding the chain of custody of the soiled masks from the point of collection in the health care facility, to the reprocessing facility, through the reprocessing cycle, repackaging, and distribution back to the health care facility include:
  • A description of the safety considerations through each step. At the facility where reprocessing will occur, also include a description of the safety considerations which will be in effect.
  • Traceability on the number of times a specific type of mask has been subjected to reprocessing.
• Long-term storage of unused respirators:
  • Stocks of expired single-use respirators can be used to protect health care personnel provided that: 1) masks were safely stored in a place without exposure to the sun, excess humidity or pests (e.g. insects, rodents); and 2) samples show that they are in good working condition, well-fitting (after a fit check) and without any deterioration (e.g., elastic bands and the nose bridge).
  • Masks are required to be stored in humidity-controlled conditions between 15 to 27 Celsius in locations that minimise physical damage, contamination, dust, and exposure to sunlight and damaging chemicals.

Canadian Scan

• Health Canada advises labelling and storage of used/reprocessed masks for health care facilities as follows:
  • Maintain supply separation between reprocessed N95 respirators and certified N95 respirators;
  • Identify and clearly mark separate areas for clean reprocessed and used reprocessed N95 respirators; and
  • Clearly label reprocessed N95 respirators as reprocessed and include instructions that indicate that they: 1) may not meet all the manufacturer’s specifications; and 2) are not re-certified as an N95 respirator.
• In Alberta, the recommended handling and storage process includes:
  • Before donning PPE, health care providers (HCP) use black sharpie to mark N95 respirator with employee ID, designation, unit number, and tally marks on the front edge of the respirator.
  • Keeping N95 on, HCP doffs PPE following patient care and inspects N95 using a mirror or buddy to assess if the N95 mask is visibly soiled, ripped or has torn elastics.
  • HCP places contaminated N95 in labelled, designated collection bucket (or rigid structure to ensure respirators are not damaged during transport) located in the PPE doffing area.
  • Health care worker (HCW) dons contact and droplet PPE.
    • Puts lids on buckets of contaminated N95 respirators in PPE doffing areas, and
    • Puts sealed buckets into designated room, wipes outside of buckets with disinfectant wipe.

Ontario Scan

• Ontario Health advises that if used masks are not visibly soiled or damaged, they should be collected and stored in disposal receptacles that are clearly labelled, dated, and separated from other types of PPE (e.g., in a biohazard bag, paper bag, or box).
  • Ensure inspection of respirators before reprocessing to confirm the condition of the N95 respirators are suitable for reprocessing if they have been stored for a length of time.
  • Consider the feasibility of individual tracking versus universal pooled supply, as both are safe approaches. In either case, users will continue to wear the same type of N95 respirator for which they have been fit-tested, and appropriate fit is further confirmed through a careful user-seal check at the point of care.

The COVID-19 Evidence Synthesis Network is comprised of groups specializing in evidence synthesis and knowledge translation. The group has committed to provide their expertise to provide high-quality, relevant, and timely synthesized research evidence about COVID-19 to inform decision makers as the pandemic continues. Ontario Health (Quality) contributed an Excel table of scientific evidence abstracts with the outputs of a MEDLINE database search conducted September 16, 2020 and a Word table of jurisdictional evidence also conducted September 16, 2020. These products were used to develop this Evidence Synthesis Briefing Note.