A lack of personal protective equipment (PPE), including N95 respirators, was one of the major reasons why surgery centers nationwide closed their operating rooms (ORs) to elective surgery during the COVID-19 pandemic.

A new study suggests a solution that involves disinfecting N95s so they can be reused for weeks. A team that includes surgeons devised a reproducible and scalable process for disinfecting N95 respirators.1

The team developed a disinfection process that includes vaporized hydrogen peroxide (VHP) and ultraviolet radiation, says Shaina R. Eckhouse, MD, FACS, assistant professor of surgery at Washington University School of Medicine in St. Louis.

N95 respirator masks and other PPE were in short supply in March and April, so the health system followed federal guidelines for extending their use. “We ran our first N95 disinfection run on April 1,” Eckhouse reports.

Eckhouse wears an N95 respirator with a regular mask over the respirator while in the OR. Her own N95 respirator was disinfected twice over a three-week period. “I put a mask over [the respirator] to help protect it and to prevent gross soilage,” she explains.

Everyone receives his or her own N95 because it ensures these will fit them well and it provides some sense of security. Each disinfection process takes 24 hours. Since everyone owns one N95 respirator, they were encouraged to wear the same N95 until they have a day off.

When they send out their N95 respirator for cleaning, it is labeled so the respirator will be returned to the original user. Unless the N95 is damaged or contains visible soilage, it can be disinfected up to 20 times, Eckhouse notes.

“If the N95 has visible soilage or is exposed to any liquid, we discourage disinfection and strongly recommend getting a new N95 mask,” she says.

The disinfection process has worked well and was extended to multiple hospitals, post-acute care facilities, and to surgery centers in the region.

“We have one surgical center that is open and that will start using our N95s,” Eckhouse reports. “They do time-sensitive cases — it’s not an emergency, but if surgery is not performed the function of the limb will be undermined with waiting.”

The disinfection process works like this:

Pick up the N95. The healthcare provider places the used N95 respirator in a Tyvek pouch and closes it with self-sealing adhesive tape. The pouch is labeled with the person’s employee identification number or name, the hospital and department, and the unit’s location.

Every 12 hours, someone picks up the pouches, inspects them for proper labeling, and transports them to the VHP room.

“The N95s are picked up in the evening, at the end of a shift. First thing in the morning, 7:30 a.m., we start the VHP process, which takes a little less than four hours,” Eckhouse says. The Tyvek pouches are not reused.

Designate disinfection area. “We have a completely separate ... four-room area for the vaporized hydrogen peroxide disinfection room,” Eckhouse says. There also is an aeration room, a common workspace, and a soiled utility area. The areas include access to hand hygiene and eye washing stations.

The N95 respirator collection bins are staged on wire racks in the soiled utility area. When the VHP room is sealed and closed, the Bioquell Z-2 disinfection cycle starts, lasting 4.5 hours. After each disinfection cycle, biological indicators are used to show whether the disinfection cycle was successful. This is followed by aeration.

Drop off N95. After aeration, the disinfected N95 respirators are placed in new Tyvek pouches and dropped into clean bins. They are arranged alphabetically and returned to pick-up locations.

As hospitals stock up on N95 respirators, collecting enough to last for a month or so, they could issue two to each employee who needs them. This way, an employee could wear one while the other is cleaned and not have to schedule the disinfection process for their days off. “Our hope is that we created a process that is reproducible in a quick manner,” Eckhouse says.

Evidence-based disinfection processes are another resource for healthcare providers to employ when PPE are in short supply, Eckhouse notes.

Creating a safe and effective disinfection process for N95 respirators makes it possible for hospital ORs and surgery centers to reuse the equipment during a crisis and PPE shortage. This disinfection process also could prove helpful to surgery centers as they reopen for elective procedures.

“Now that we have this process in place, we are hoping to get back to elective surgery here in the near future,” Eckhouse says. “I am a bariatric surgeon, truly elective surgery. I’m involved in perioperative services leadership.”

When the pandemic and PPE shortage are over, some may begin to use N95 respirators as single-use items again.

“Once the demand drops, and N95 supply increases, we’ll go back to normal uses of N95 respirators,” Eckhouse reports. “But in the future, if another pandemic hits, we can utilize the processes we’ve developed to set up this in a shorter time frame.”


  1. Grossman J, Pierce A, Mody J, et al. Institution of a novel process for N95 respirator disinfection with vaporized hydrogen peroxide in the setting of the COVID-19 pandemic at a large academic medical center. J Am Coll Surg 2020;S1072-7515:30349-30355.