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Who is at risk?

Ozone is commonly found at water treatment plants where it is used to disinfect municipal and industrial waste water.

Drinking water treatment facilities use Ozone to reduce or overcome colour and taste whilst also destroying bacteria and inactivating viruses. Significant quantities of Ozone are also produced during TIG and MIG welding processes.


Sharp odour resembling chlorine bleach


Ozone is amongst the most toxic air pollutants, irritating and enflaming the lining of the lungs. Short term effects include coughing and difficulty breathing which leads on to reduced lung capacity and accelerated aging of the lungs.

Acute Exposure

Concentration Effect
0.003 - 0.010 ppm Detectable odour in air
0.001 - 0.125 ppm Typical concentrations is natural atmosphere
0.5 ppm Nausea and headaches in some individuals
1 - 2 ppm Headache, pain in chest and dry throat
9 ppm Pulmonary edema, fatigue and difficulty breathing
> 25 ppm Immediately hazardous to human health
50 ppm Fatal after 1 hour exposure

Exposure Controls & Protection

NFPA 704 Signal

  Hazard Value Description
Health 4 Can be lethal.
Flammability 0 Will not burn under typical fire conditions.
Instability 4 Readily capable of detonation or explosive decomposition or explosive reaction at normal temperatures and pressures.
Special OX Possesses oxidizing properties