Chlorine dioxide / ClO₂

Chlorine dioxide

Gas Identification

Other denomination
Chlorine oxide, Chlorine peroxide, Chlorine (IV) oxide
CAS Registry Number
SCBA type

Chemical properties

Molecular formula
Molecular mass

Physical properties

Boiling point
Autoignition temperature
Gas/Vapour density
10,33 eV

Flammability limit


Threshold limit value

0,1 ppm • 0,3 mg/m³
0,3 ppm • 0,8 mg/m³

Chlorine dioxide : Description and use


Chlorine dioxide (or chlorine bioxide) is one of many known chlorine oxides. Chlorine dioxide is relatively stable in its gaseous and liquid forms, but it is quick to explode. In practice, it is never used in its pure state.
Chlorine dioxide is a reddish-yellow gas. It has a chlorinated odour reminiscent of that of nitric acid.

Flammability: This product is flammable under the following conditions:

  • It can explode in air in concentrations of over 10%.
  • It can cause or intensify a fire in the presence of combustible material.

Chlorine dioxide is often used as a bleaching agent in the pulp and paper industry, where, for ecological reasons, it is increasingly replacing chlorine. It is also used in several other applications, though its use is more limited here:

  • in the bleaching of textile fibres
  • as a disinfectant in many drinking water treatment plants
  • in the food industry for microbe control
  • in the oil fields for the removal of biofilms
  • for controlling odours or neutralising certain compounds
  • Chlorine dioxide : Warnings and caution

    GHS hazard statements

    H270 - May cause or intensify fire; oxidiser.
    H280 - Contains gas under pressure; may explode if heated.
    H314 - Causes severe skin burns and eye damage.
    H330 - Fatal if inhaled.
    H400 - Very toxic to aquatic life.

    EUH006 - Explosive with or without contact with air.

    GHS precautionary statements

    P260 - Do not breathe gas.
    P271 - Use only outdoors or in a well-ventilated area.
    P280 - Wear protective gloves/protective clothing/eye protection/face protection.
    P284 - Wear respiratory protection.
    P304+P340 - IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing.
    P403+P233 - Store in a well-ventilated place. Keep container tightly closed.
    P220 - Keep/Store away from combustible materials.
    P305+P351+P338 - IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
    P309+P311 - IF exposed or if you feel unwell: Call a POISON CENTRE or doctor/physician.

    SGH04 : Gaz sous pression
    SGH06 : Toxique
    SGH05 : Corrosif
    SGH03 : Comburant
    SGH09 : Danger pour le milieu aquatique