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CLO2 Safety Information

Chlorine dioxide is not shipped in commerce or stored for any significant period of time because it is a highly reactive "free radical" molecule. Instead, CLO2 is generated on-site in a safe working concentration level at the location and time of its use.

The OdorXit CLO2 generation process produces high purity CLO2 through the controlled reaction of two common industrial materials. These materials are one of several crystalline and hygroscopic acids, any of several buffering materials and sodium chlorite (16%). The materials are placed in a Tyvek® reactor pouch with an internal membrane to separate the sodium chlorite from the other materials. When the reactor packet is exposed to 40% relative humidity or more, an acid slurry is produced and migrates through the membrane to the sodium chlorite where it reacts and produced high purity CLO2 gas that escapes through the Tyvek welds around the edge of the packet.

At the concentration level produced by the AQM products when used as directed, the CLO2 produced is extremely safe to handle, be around and apply as either a liquid or a gas.

CLO2 gas at .003 to .01 PPM in air is completely safe for 24/7 exposure according to EPA guidelines, higher concentrations up to 1 PPM can safely be tolerated for up to 15 minutes. CLO2 gas does not become unstable until a 10 to 15% (100,000 to 150,000 PPM) concentration in air is reached. These extremely high concentrations can be reached by reacting a packet in a closed container or ZIPLOC bag which can be highly dangerous.

A 300 ppm solution of CLO2 is a non-flammable liquid with a vapor pressure and boiling point essentially the same as water (i.e. 20 mm Hg barimetric pressure) 212 degrees F (100ºC). In addition, a 300 ppm solution of CLO2 is minimally irritating to the eyes and non-irritating to the skin, so long as the pH of the solution is maintained in the neutral range. Although good hygiene practice always dictates the use of eye and skin protection when working with liquid chemicals, ordinary work clothes may otherwise be worn when generating and applying CLO2 solutions in this concentration range.


The toxicology of CLO2 has been studied extensively, particularly with regard to exposure through ingestion, because CLO2 is widely used in disinfectant and food sanitation applications. The USEPA has established a Reference Dose (RfD) of 3x10-2 mg/kg/day, based on findings of a two-generation reproduction drinking water study in the rat that identified a No Observed Adverse Effect Level of 3 mg/kg/day (35 ppm chlorite) and a Lowest Observed Adverse Effect Level of 6 mg/kg/day (70 ppm chlorite) (neurodevelopmental effects). The RfD has been used by USEPA to derive drinking water standards, including a Maximum Residual Disinfectant Level of 0.8 ppm for CLO2 and a Maximum Contaminant Level of 1.0 ppm for chlorite ion, the principal breakdown product of CLO2. Drinking water is by far the largest source of human oral exposure to CLO2 and chlorite.


There are no data available for CLO2 carcinogenicity because it does not persist in the environment. However, the major decomposition product, chlorite ion, has been tested for carcinogenicity in animals. The data in rats and mice do not associate chlorite ion with cancer.


By inhalation, excessive exposure to CLO2 has been shown to cause adverse health effects that are largely related to its irritant properties. The most likely health effects associated with excessive CLO2 exposure include: irritation of the eyes, nose and throat; coughing; wheezing; shortness of breath; bronchitis; pulmonary edema; and headache. The American Conference of Governmental Industrial Hygienists (ACGIH) and the Occupational Safety and Health Administration (OSHA) have both established an eight-hour time-weighted average (TWA) exposure standard of 0.1 ppm. The 0.1 ppm ACGIH/OSHA standard represents the airborne concentration of CLO2 to which it is believed that nearly all healthy adult workers may be repeatedly exposed, day after day, over a working lifetime, without experiencing any adverse health effects. The ACGIH has also established a short-term exposure standard (STEL) of 0.3 ppm for CLO2. Exposures at the STEL concentration should not be repeated more than four times a day and should be separated by intervals of at least 60 minutes.

USEPA Standards

In order to ensure protection of sensitive subgroups within the general population during gaseous CLO2 applications, the USEPA has also developed a rolling 15-minute TWA environmental exposure standard of 0.025 ppmv that is applicable at the "fenceline" of each facility undergoing treatment. Experience gained during previous large-scale CLO2 fumigation projects demonstrates that compliance with this standard is readily achievable. CLO2 can be effectively contained within a treatment zone or building during fumigation through either of two basic strategies. The building can be sealed as tightly as possible with tape, expandable foam, etc. and a negative pressure pulled sufficient to prevent CLO2 from leaking out cracks, crevices, etc. or a "tent" can be constructed over the entire facility and a slight negative pressure pulled to seal the tent to the structure. The decision regarding which containment approach to take during a given fumigation is highly dependent upon characteristics of the building, economics and other attendant circumstances.

CLO2 Safety Documentation

Material Safety Data Sheets (MSDS):

Updated July, 2016

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