By Duane S. Daggers, Jr., MS, OSH, ASHM, NREMTP
The COVID-19 pandemic caused serious issues for our workforce. With so many people needing PPE, it became nearly impossible to find the supplies we needed. Additionally, PPE from outside the United States is not approved for first responders and healthcare workers. These issues left us with few options.
One of most realistic options was to approve a process for sanitizing used PPE, but we had to ensure the safety of our personnel in the process.
Because N95 respirators, surgical masks and disposable gowns are designed for one-time use, neither the manufacturers nor standardizing agencies (OSHA, NIOSH, etc.) would approve nor guarantee protection for extended or multiple use. But as the magnitude of the pandemic grew, so did the need to establish an avenue for workers to keep appropriate PPE on hand.
Even though the CDC established criteria for extended use of our on hand PPE items, our workforce was still going to need to identify a way to ensure that we kept an available supply of PPE on hand. With numerous city departments directly interacting with the public, our supply in extended use was still going to be challenged due to our city’s inability to find suppliers with stock to resupply what we have used.
Duke studies vaporized hydrogen peroxide
The need for approving a process of sanitizing PPE is not new to our nation. In 2016, the H1N1 pandemic saw supplies of PPE depleted. To combat this threat, researchers studied several sanitizing agents to identify a safe method of sanitizing PPE.
Of the agents tested, vaporized hydrogen peroxide had very positive results. The peroxide process did not significantly affect overall airflow performance, and off-gas vapors decompose into water vapor and oxygen, which are safe (Dennis J. Viscusi, 2009).
This study provided great information, but they never completed the research with post-sanitization quality control. As the 2016 pandemic came to an end, there was no longer an emphasis to identify a method – until now.
New research, which was verified with quality control studies, was completed by specialists from Duke University in March. I had the opportunity to discuss their process with Dr. Cameron Wolfe, who headed the research project, as well as Mike Martens, MS, ASP, REP, EMT-P, the Environmental Health and Safety Program Manager for the Sentara Healthcare Organization.
The Duke University Health research team was led by Occupational and Environmental Safety Health Director Nicole Greeson, a certified industrial hygienist, and Dr. Wolfe. Wolfe shared with me the completed research about a process involving sanitization using vaporized hydrogen peroxide (Stradling, 2020).
The process: They pour a 30-35% concentrated hydrogen peroxide solution and proportion the concentrate into a 5-7% mixture. The process takes about eight hours and involves a five-stage progression:
- Gas dwell
Martens outlines the benefits of the peroxide process:
- No toxic by-products like chlorine, ammonia or hydrogen peroxide converts to water in the air following the procedure and evaporates.
- Hydroxyl radical is produced by altering hydrogen peroxide mechanically. This is done typically by a redox transition between metals (copper, iron, etc.) and hydrogen peroxide.
- Free hydroxyl radicals destroy lipids, proteins, carbohydrates and pathogens (bacteria, viral, fungal).
- Oxidization happens at the cellular level and highly reactive to the pathogen.
- EPA/FDA-approved and most effective disinfectant methodology on the market today. Used during Anthrax scare in 2001 (Martens, 2020).
The Duke study documented that the hydrogen peroxide process was safe and efficient.
Implementing the process locally
The challenge now was adapting this process in our area.
Martens and the Sentara team identified a local safety company that was successfully completing a similar sanitization process. This could be the big break our city needed, but more research needed to be done. Our department wanted specific details on the process.
Sanair Indoor Air Company partnered with Sentara Healthcare, and Sanair established a sanitizing operation in the City of Chesapeake (COC).
Meeting with Sentara safety professionals and the president of Sanair allowed COC Office of Emergency Management to gather data on its current process and compare it to the established process from Duke University.
It was ultimately determined among COC, Sentara and Duke that the processes are similar in product, and their procedures have implemented changes in engineering controls that make this process unique.
One difference: Sanair also uses peroxide, but the percentage, soak time and dwell time are different. They also ionize, which brings a small electric charge to the process, helping it permeate all layers of the masks. In addition, they also introduce a surfactant, which decreases surface tension, thus further allowing permeation.
Here’s the comparison:
- Agent – 30% peroxide, proportioned to 7-8 %
- Complete room gas immersion
- Soak time – 25 minutes
- Dwell time – 20 minutes
- Ventilation, drying, complete process time – 4 hours
- Agent – 20% peroxide initial product, dispersed for sanitizing at 7% solution
- Two-phase gas process
- Direct application via vaporizing wand
- Complete room gas immersion
- Ionization and surfactant included
- Soak time – 30 minutes
- Dwell time – 2 hours
- Ventilation, drying, complete process time – 8 hours
Quality controls are in place to monitor the atmosphere in the sanitizing area as well as the ambient area outside. It was important to capture that during the gas and soak cycles, the peroxide concentration remained consistent for the duration, and that the area around the area remained safe.
By monitoring these areas, they were able to show the hydrogen peroxide parts per million in the gas room remained within their set variance, and the area around it was monitored to detect any changes to the oxygen concentration or the introduction of hydrogen peroxide. The levels remained unchanged.
During the ventilation process, the ambient area used for exhausting was monitored for any changes in oxygen concentration or the introduction of any harmful toxins. The monitoring confirmed the byproducts of the process were oxygen and water vapor.
Controls are also in place to inspect the units before and after a process to ensure no units are being returned that failed the inspection or sanitation process. Also, testing is being performed by an independent lab as well as by Sentara’s staff for additional quality control on the masks themselves.
This process is good for 20 cycles per unit.
The post-sanitizing testing confirms there are no harmful by products of sanitizing, wearers experience no ill effects from use, and atmospheric testing confirms all items pass fit testing. And with that, the decision was made to begin a sanitizing procedure for our city’s PPE. In order to maintain accountability and ensure our safety, the COC EOC has implemented a stand-alone unit specifically focused on the sanitizing process of our PPE.
Program results – and firefighter comments
The program has been extremely successful. As many areas slowly begin Phase 1 recovery plans and openings, our city is still exercising strict PPE standards. The PPE sanitizing process has successfully inspected, sanitized, re-inspected and returned close to 1,200 masks. These masks have been used by several members across multiple city departments in training evolutions designed by the PPE Unit.
What workers have found is that the sanitized masks look cleaner and smell cleaner than the new masks out of the shipping box. The critical component in this entire process has been that as a city, we have been able to keep a vital item for successful operations readily available with a process that is in our local area. The time to have masks back in service has guaranteed the success of our PPE stock.
ABOUT THE AUTHOR
Duane Daggers is a 35-year veteran of the fire service. He is a fire captain with the City of Chesapeake (Virginia) Fire Department and is a life member with the Gouldsboro (Pennsylvania) Volunteer Fire Company. He has been an active instructor for over 20 years. He holds a master’s degree in occupational safety and health, a bachelor’s degree in organizational leadership and management, and associate degrees in fire science and emergency management.
Dennis J. Viscusi, M. S. (2009, October 4). Evaluation of Five Decontamination Methods for Filtering Facepiece Respirators. The Annals of Occupational Hygiene, 53(8), 815-827.
Martens, M. (2020, March). Follow up on Peroxide Sanitizing. Norfolk, VA, USA.
Stradling, R. (2020, March 26). Duke says it has found a way to safely reuse masks worn when treating COVID-19 patients. Retrieved from The News Observer: https://www.newsobserver.com/news/coronavirus/article241520921.html