Biosafety cabinet decontamination: chlorine dioxide versus aporized hydrogen peroxide
Here at American Instrument Exchange we use the chlorine dioxide decontamination method for our biological decontaminations.
When conducting a decontamination the primary concern must be the efficacy of the decon method. Chlorine dioxide is a true gas and as such it will fill the space it is injected to (“Method Comparisons” 2014). This means that no outside manipulation is required to ensure that the chlorine is completely filling the available space, ensuring that the decontamination is 100% effective and that the equipment is subsequently safe to be worked on, moved, new experiments can be conducted, etc.
Vaporized hydrogen peroxide (VHP) is not a true gas and therefore does not naturally fill spaces. In larger spaces, outside manipulation such as a fan is required to ensure the gas is encountering all surfaces (Sawyer, Pierzynski, Trapp, n.d.). In a biological safety cabinet, there is no way to verify all surfaces behind the HEPA filters have been adequately decontaminated. In other words, there isn’t any confirmation that the decontamination method was effective.
Chlorine dioxide also has a yellowish color and a very distinct smell. When there is a leak present in the decontamination process it is quickly apparent and steps can be taken to ensure the problem is resolved. If the leak cannot be found in a timely manner the decontamination process can immediately be aborted and the chlorine gas can be neutralized. This ensures the safety of the technicians conducting the decontamination and any other personnel present. VHP does not have any distinct smell or color, and therefore cannot be detected until the gas has reached unsafe levels in the event of a leak.
More importantly, aeration times are far faster with chlorine dioxide when compared to VHP. Chlorine dioxide aerates a space withing about 30 minutes, whereas VHP requires overnight aeration (“Safety,” 2014).
When performing a chlorine dioxide decontamination we mix the required, proprietary chemicals in a Pyrex bowl to initiate the process of decontamination. This simple method allows us the freedom to set off multiple decontaminations in a day, unlike other processes that require equipment to be attached through the entire decontamination, limiting the number of units that can be decontaminated each day to the number of units the company has. Once the gas has penetrated the entire space we use a carbon scrubber to neutralize any remaining gas.
We recognize that there are some downfalls to using chlorine dioxide over VHP. Because chlorine is a true gas, for example, the process is more susceptible to leaks. Any small issue with the sealing process will allow for the gas to escape into the outside space. We mitigate this risk by adding a chlorine detector to our process, a step above the NSF required safety recommendations.
In most cases, chlorine dioxide should be the preferred method of decontamination. Its natural ability to fill space ensures that all surfaces in the cabinet are encountering the gas, and therefore provides a greater degree of confidence that the decontamination was truly effective. The odor allows individuals to detect there is a problem, long before the gas has reached dangerous levels, and can be rectified immediately to ensure no harm comes to anyone in the facility. The process also allows for a greater number of units to be decontaminated in a day and is also a much faster process to complete. This reduces the amount of time equipment needs to be out of service, allowing facilities to get up and running faster than VHP.
Compatibility of Material and Electronic Equipment With Hydrogen Peroxide and Chlorine Dioxide Fumigation (2010). file:///C:/Users/User/Downloads/COMPATIBILITY%20OF%20MATERIAL%20AND%20ELECTRONIC%20EQUIMENT%20WITH%20HYDROGEN%20(1).PDF
Method Comparisons: Hydrogen Peroxide (2014) https://www.clordisys.com/methodvhp.php
Safety (2014). https://www.clordisys.com/safety.php
Sawyer, M., Pierzynski, J., Trapp, M. (n.d.). Got Gas? Chlorine Dioxide or Vaporized Hydrogen Peroxide: Which one is right for you? https://www.bri.k-state.edu/biosketches/publications/POSTER-Web.pdf
Here at American Instrument Exchange we use the chlorine dioxide decontamination method for our biological decontaminations.
When conducting a decontamination the primary concern must be the efficacy of the decon method. Chlorine dioxide is a true gas and as such it will fill the space it is injected to (“Method Comparisons” 2014). This means that no outside manipulation is required to ensure that the chlorine is completely filling the available space, ensuring that the decontamination is 100% effective and that the equipment is subsequently safe to be worked on, moved, new experiments can be conducted, etc.
Vaporized hydrogen peroxide (VHP) is not a true gas and therefore does not naturally fill spaces. In larger spaces, outside manipulation such as a fan is required to ensure the gas is encountering all surfaces (Sawyer, Pierzynski, Trapp, n.d.). In a biological safety cabinet, there is no way to verify all surfaces behind the HEPA filters have been adequately decontaminated. In other words, there isn’t any confirmation that the decontamination method was effective.
Chlorine dioxide also has a yellowish color and a very distinct smell. When there is a leak present in the decontamination process it is quickly apparent and steps can be taken to ensure the problem is resolved. If the leak cannot be found in a timely manner the decontamination process can immediately be aborted and the chlorine gas can be neutralized. This ensures the safety of the technicians conducting the decontamination and any other personnel present. VHP does not have any distinct smell or color, and therefore cannot be detected until the gas has reached unsafe levels in the event of a leak.
More importantly, aeration times are far faster with chlorine dioxide when compared to VHP. Chlorine dioxide aerates a space withing about 30 minutes, whereas VHP requires overnight aeration (“Safety,” 2014).
When performing a chlorine dioxide decontamination we mix the required, proprietary chemicals in a Pyrex bowl to initiate the process of decontamination. This simple method allows us the freedom to set off multiple decontaminations in a day, unlike other processes that require equipment to be attached through the entire decontamination, limiting the number of units that can be decontaminated each day to the number of units the company has. Once the gas has penetrated the entire space we use a carbon scrubber to neutralize any remaining gas.
We recognize that there are some downfalls to using chlorine dioxide over VHP. Because chlorine is a true gas, for example, the process is more susceptible to leaks. Any small issue with the sealing process will allow for the gas to escape into the outside space. We mitigate this risk by adding a chlorine detector to our process, a step above the NSF required safety recommendations.
In most cases, chlorine dioxide should be the preferred method of decontamination. Its natural ability to fill space ensures that all surfaces in the cabinet are encountering the gas, and therefore provides a greater degree of confidence that the decontamination was truly effective. The odor allows individuals to detect there is a problem, long before the gas has reached dangerous levels, and can be rectified immediately to ensure no harm comes to anyone in the facility. The process also allows for a greater number of units to be decontaminated in a day and is also a much faster process to complete. This reduces the amount of time equipment needs to be out of service, allowing facilities to get up and running faster than VHP.
Compatibility of Material and Electronic Equipment With Hydrogen Peroxide and Chlorine Dioxide Fumigation (2010). file:///C:/Users/User/Downloads/COMPATIBILITY%20OF%20MATERIAL%20AND%20ELECTRONIC%20EQUIMENT%20WITH%20HYDROGEN%20(1).PDF
Method Comparisons: Hydrogen Peroxide (2014) https://www.clordisys.com/methodvhp.php
Safety (2014). https://www.clordisys.com/safety.php
Sawyer, M., Pierzynski, J., Trapp, M. (n.d.). Got Gas? Chlorine Dioxide or Vaporized Hydrogen Peroxide: Which one is right for you? https://www.bri.k-state.edu/biosketches/publications/POSTER-Web.pdf