July 22, 2024


Make Every Business

St. Louis surgeons create new process for disinfecting and reusing N95 masks

Amid shortages of personal protective equipment due to the COVID-19 novel coronavirus pandemic, a St. Louis healthcare system has implemented a process to disinfect disposable N95 respirator masks that allows healthcare workers to reuse their own mask for up to 20 cycles.

The disinfection process, developed in collaboration with Washington University School of Medicine, uses vaporized hydrogen peroxide and is described in an article in press in the Journal of the American College of Surgeons.

Test results from the pilot program at Barnes-Jewish Hospital, and two other hospitals that are also part of BJC HealthCare, showed the disinfection process kills germs from N95 masks while ensuring that the only person who touches the mask is the original mask wearer.

Their program uses a disinfecting procedure first tested by Duke University researchers in 2016. But the Barnes-Jewish process has a unique modification: an identification system that enables the hospital to return the sanitized mask to the same individual each time.

This approach, according to the authors, increased employee acceptance of reusing what is normally a single-use N95 mask and helped ensure proper fit of the returned mask.

In late March, before the program began, Barnes-Jewish had a low inventory of N95 masks — about a week’s worth — and no expectations for replenishment because of international shortages in hospital supply chains.


The disinfection process that has since been put into place begins at the end of a shift. A healthcare provider removes his or her N95 mask in that unit’s soiled utility room and places it in a Crosstex sterilization pouch made of breathable polyethylene fiber on one side. On the other side of the sealed pouch, the worker writes his or her name or employee ID number, hospital, department, and unit location and puts the pouch in the soiled collection bin.

A designated worker wearing proper protection collects the bins twice a day and takes them to a specially designed and sealed disinfection room, which was built in four days. There, the pouches are arranged, breathable side up, by clinical unit on wire racks. A hydrogen peroxide vapor generator (Bioquell Z-2), which Washington University already owned to decontaminate equipment, fills the room with the chemical.

After 4.5 hours of disinfection, a worker moves the racks of masks to another area that has a fan to offgas the hydrogen peroxide, where the masks stay until sensors record a zero reading. The pouches are returned to their respective units in a decontaminated bin, finishing a process that takes about seven hours.

Workers can wear their mask up to three weeks. Past studies show that disinfection of more than 20 times could alter the fit of the mask. Since the program began April 1 in the Barnes-Jewish emergency department, it expanded in just two weeks to additional clinical departments and other hospitals in the system.

Currently, the hospital is disinfecting 240 N95 masks a day and has the capability of disinfecting 1,500 masks daily. Without the disinfection program, authors said, the health system would need to discard a substantial amount of its respirator masks. Because of the disinfection, the hospitals now have enough masks to last for weeks.

Other hospitals facing mask shortages can reproduce the disinfection program if they bring together experts in environmental health and safety, medicine, and facility management, the findings showed.


During the COVID-19 pandemic, the Centers for Disease Control and Prevention has recommended strategies for conserving personal protective equipment, including decontamination and reuse of N95 masks.

Almost half of U.S. healthcare facilities reported being nearly or completely out of N95 respirator masks, according to a March 27 survey conducted by the Association for Professionals in Infection Control and Epidemiology.

The mask shortages coincide with insufficient tests for COVID-19, slow results and shortages of ventilators for critically ill patients, and these problems are interconnected, making each other worse in a toxic cycle.

Twitter: @JELagasse

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