Wednesday, July 10, 2019

Chlorine Dioxide: The Safest of all Decontaminating Agents

All decontamination methods have a safety risk due to the nature of their use. Because of that, a variety of aspects should be considered to ensure that the process will be safe for your environment and employees. Gaseous chlorine dioxide (CD) can be used safer than other fumigation methods due to its chemical properties and safety profile.

The best safety feature with CD gas is that it is self-alerting. Chlorine dioxide has an odor threshold at or below the 8-hour Time Weighted Average (TWA), so the user is self-alerted to exposure at a low level and the reliance on external equipment is not as imperative. With Vapor Phase Hydrogen Peroxide (VPHP), there is no odor to provide a warning of exposure. This alone makes CD gas safer since the user and nearby personnel are self-alerted before unsafe levels are achieved, and the reliance upon external equipment is less critical.

Chlorine dioxide gas has a shorter cycle time than other high level decontamination methods, lowering the risk profile for the process itself.  Decontaminating a 10” x 20” room would take approximately 3.5 hours from start to end when it is safe to reenter the room.  Formaldehyde would be about 12.5 hours, and VPHP could be 10+ hours. VPHP has longer cycles because of the extended aeration times due to the nature of vapor condensation and absorption issues that do not apply with a true gas. Formaldehyde has long cycles because of long exposure times and the neutralization time. A longer cycle time represents a greater risk as the room contains an unsafe environment throughout the decontamination process.  CD gas is able to reduce the risk by completing its decontamination cycle in a much shorter time while still delivering a complete, 6-log decontamination of the room.
Chlorine dioxide is typically used at lower concentrations for room decontamination. VPHP concentrations are typically 750-1500 ppm. Formaldehyde concentration is typically 10,000 ppm. CD concentration is typically 360 ppm. Use concentrations for all agents are much higher than safe levels, however if something goes wrong, the higher concentration of formaldehyde and VPHP poses a greater risk.

The chlorine dioxide gas generating equipment is located outside the room or chamber being decontaminated.  If equipment is inside the room and some issue occurs, the possibility exists where the user may have to enter the during unsafe conditions in order to shut the equipment down.  Since our CD generation equipment is located outside the chamber, if an issue occurs, the equipment can easily be shutdown by hitting the stop button located on the generator or simply pulling the plug.

Chlorine dioxide gas is not classified as a carcinogen by any health organization.  Chlorine dioxide is used to treat drinking water in over 800 municipalities within the United States, and it is widely used in Europe as well.  Chlorine dioxide is also on the National Organic Program’s List of Approved and Prohibited Substances as an approved substance for use in organic foods. Formaldehyde is classified as a known carcinogen by most of the leading health organizations worldwide, and the American Conference of Governmental Industrial Hygienists (ACGIH) designates VPHP as an A3, Confirmed Animal Carcinogen with Unknown Relevance to Humans.

One of the most important safety factors for decontamination methods are their ability to completely decontaminate the space they are introduced into.  Chlorine dioxide and formaldehyde are gasses which reach and penetrate all areas throughout the room/chamber including cracks, crevices and other hard to reach areas.  Vapors have difficulty reaching these areas due to poor diffusive properties and condensation issues. If the decontaminating agent cannot reach ALL of the dangerous organisms in the space, at the proper concentration, for the prescribed amount of time, then a complete decontamination will not occur and worker safety is compromised. CD gas is able to be accurately measured in real-time using a UV-vis spectrophotometer, allowing for the correct concentration and exposure levels to be met every time, making it very reliable.

For more safety facts and method comparisons, visit our website.