Wearing a face mask helps to protect yourself and others from COVID-19. But when supplies are limited, should you reuse your mask? Are there safe ways to decontaminate your N95 and KN95 masks? Your safety is critical during the times we’re living in, so we’ve compiled a list of tips to help you properly protect yourself.

The first thing to understand is that most face masks, N95, KN95, and surgical masks, are all intended to be used one time, discarded, and replaced with a new mask.

With that reminder, our recommendation is to always replace your face masks after each use, if possible. However, we understand that PPE (Personal Protective Equipment) supplies are in high demand, and reuse may be necessary.

How long can you reuse N95, KN95, or surgical masks for?
The CDC clearly states that there is no way to recommend exactly how many times you can reuse your mask, as every situation has many variables to consider. Therefore, how long you reuse your mask depends on your personal comfort, environmental factors, and potential contamination. The CDC suggests the following considerations if your healthcare facility permits reuse:

  • Consider the use of a cleanable face shield (preferred3) over an N95 respirator and/or other steps (e.g., masking patients, use of engineering controls), when feasible to reduce surface contamination of the respirator.
  • 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.
  • Clean hands with soap and water or an alcohol-based hand sanitizer before and after touching or adjusting the respirator (if necessary for comfort or to maintain fit).
  • Avoid touching the inside of the respirator. If inadvertent contact is made with the inside of the respirator, discard the respirator and perform hand hygiene as described above.
  • Use a pair of clean (non-sterile) gloves when donning a used N95 respirator and performing a user seal check. Discard gloves after the N95 respirator is donned and any adjustments are made to ensure the respirator is sitting comfortably on your face with a good seal.

Extended Use
The CDC reports that prolonged N95 mask use (including between patients) can be safe for up to 8 hours, and encourages each user to review each manufacturer’s recommendations prior to following this strategy. Current guidelines encourage wearing a face shield over the N95 to decrease the chances of soiling the mask.

Because coronaviruses lose their viability significantly after 72 hours, many organizations have promoted a rotation and re-use strategy. Assuming there is no soiling and minimal to no viral contamination to the mask, the CDC suggests that masks can be re-used up to 5 times with the following mask rotation strategy:

  • Acquire a set number of N95 masks (at least 5 per the CDC), and rotate their use each day, allowing them to dry for long enough that the virus is no longer viable (> 72 hours).
  • Proper storage for this technique requires either hanging the respirators to dry, or keeping them in a clean, breathable container like a paper bag between uses.
  • Make sure the masks do not touch each other, and that you do not share your respirator with other people.
  • A user seal check should be performed before each use.
  • Importantly, when planning to reuse an N-95 mask, practice fastidious donning/doffing to avoid contamination of the inside or outside of the mask at all times.

If you notice any deterioration of your mask or significantly contaminated from aerosol-generating procedures or bodily fluids, it should be discarded. You should thoroughly inspect the mask after each use and cleaning. Pay special attention to how well the mask is fitting—if your mask straps begin to lose elasticity it will no longer cover your face effectively and should be discarded.

Cleaning and disinfecting N95 and KN95 face masks
Proper disinfection and decontamination of N95 or KN95 face masks is a tricky business, as you need to inactivate the virus without compromising the filtration and fit of the mask. On April 15, 2020, the NIH released a study that validated decontamination methods for re-use of N95 respirators. Decontamination methods tested included vaporized hydrogen peroxide (VHP), 70-degree Celsius dry heat, ultraviolet light, and 70% ethanol spray.

All four methods eliminated the detectable viable virus from the N95 fabric test samples. The investigators from NIH’s Rocky Mountain Laboratories (RML) then treated fully intact, clean respirators with the same decontamination methods to test their reuse durability. Volunteer employees wore the masks for two hours to determine if they maintained a proper fit and seal over the face; decontamination was repeated three times with each mask using the same procedure. Here’s what they found:

  • The scientists found that ethanol spray damaged the integrity of the respirator’s fit and seal after two decontamination sessions and therefore do not recommend it for decontaminating N95 respirators.
  • UV and heat-treated respirators began showing fit and seal problems after three decontaminations — suggesting these respirators potentially could be re-used twice.
  • The VHP-treated masks experienced no failures, suggesting they potentially could be re-used three times.

Can I wash or decontaminate an N95 mask or a KN95 mask at home?
The short answer is no… There are two things you should definitely NOT do with any N95 or KN95 mask:

  • Spraying or wetting with aerosol or liquid alcohol.
  • Washing in soapy water.

N95 face masks that have a paper outer and inner layer should not be boiled, steamed, or washed because they will disintegrate the filter medium material. Doctor Tsai of UT Knoxville performed a study that showed significant reductions in mask filtration efficiency when cleaned with alcohol or soapy water. Unlike your hands, your mask cannot be washed for proper decontamination.

What is the difference between N95 and KN95 face masks?
N95 face masks are examples of PPE that are used to protect the wearer from airborne particles and liquid contaminating the face.

They are regulated by the FDA and NIOSH (U.S. National Institute for Occupational Safety and Health). The N is for “Not resistant to oil” and the 95 refers to the minimal is efficiency level at 0.3 microns (of which is it 95% efficient).

Similarly, KN95 masks are also a form of PPE used to protect the wearer from similar hazards though they are not regulated by NIOSH. These masks are often identical to N95 masks and are the “N95 equivalent” for medical usage in China.

In the US, they are primarily used in industrial settings and offer the same filtration as N95 face masks with a rating of 95% at 0.3 Micron. In fact, these masks are often produced from the same assembly line as N95 masks however are not sent for NIOSH regulation.

On April 3rd of this year, the FDA approved the use of KN95 masks for healthcare professionals in an effort to increase the available PPE face masks and lower the spread of the COVID-19.

Reorder your KN95 masks today
While PPE supplies are in high demand, Local Health Pharmacy continues to work to secure KN95 masks, surgical masks, gloves, hand sanitizer and more to help you protect your health. These items are available at the Local Health Pharmacies in the Chicago area, and available to ship anywhere in the U.S. when you order online at www.localhealthrx.com/shop.