|Principal characteristics||Oxidising gas - CAS no. 10028-15-6 / EG no. 233-069-2|
|Concentration||Up to 18 % by weight in oxygen/oxygen-enriched air|
|Solubility in water by weight (at 20°C)||570 mg/l |
|Vapour densitiy||1.6 (1 = air)|
|Flammability||Non-flammable/vigorously supports combustion|
|Appearance and odour||Ozone is colourless at all concentrations experianced in the industry. It has a pungent characteristics odour usually associated with electrical sparks. The odour is generally detectable by the human nose at concentrations of 0.02 and 0.05 ppm.
|Fire/Explosion and hazard data||Ozone is a powerful oxidising agent. Oxidation with ozone evolves more heat and usually ignites at a lower temperature than oxidising with oxygen. Ozone reacts with non-saturated organic compounds to produce ozonides, which are unstable and may decompose with explosive voilence. Ozone is an unstable gas that, at normal temperatures, decomposes to biatomic oxygen. At elevated temperatures and in presence of certain catalysts such as hydrogen, iron, copper and chromium, this decomposition may be explosive.|
|Flash point||Not applicable|
|Auto ignition temperature||Not applicable|
Health Hazard Data
|Permissible Exposure Limits||The following limits are widly accepted (USA, Sweden, UK and other parts of Europe):|
- 8 hour per day/5 days per week (occupational exposure limit) - 0.1 ppm
- 15 minutes (short term exposure limit) - 0.3 ppm
|Toxicology of ozone||
The acute and chronic effects of excessive exposure to ozone have been well investigated. Exposure to concentrations of ozone in excess of several tenths of a ppm sometime cause reports of discomfort in a small susceptible portion of the population. This can be in the form of headaches of dryness of the throat and mucous membranes of the eyes and nose following exposures of short duration. Repeated exposure to ozone at such concentrations at 24-hour intervals, however, caused no further increase in airway irritability. In fact after the first exposures, additional exposures to ozone had progressively lesser effects suggesting that tolerance may develop over time.
Ozone has been shown to be more injurious at concentrations exceeding 2.0ppm over several hours, such as experienced by gas shielded arv welders. The primary site of acute effects is the lung which is characterized by pulmonary congestion. This acute impact subsided in welders when exposures where reduced to less than 0.2ppm. Based on animal studies, exposure over 10 to 20ppm or an hour or less believed to be lethal in humans although there has never been a single recorded fatality attributed to ozone exposure in more than 100 years of commercial use. (Compare with this experience with Chlorine as which has claimed many victims in peacetime as well as during war).
With respect to long term or chronic toxicity, ozone is a radiomimetic agent, i.e. the effects of long term exposure to excessive ozone exhibits the same affects as excessive exposure to sunlight. These effects are drying of the dermal surfaces and general ageing of exposed tissues. Ozone is not generally regarded or suspected of being a human carcinogen, neither does in exhibit tertogenic or mutagenic properties.
In the event of an ozone leak:
- Ventilate the area
- Immediately switch the ozone generator off
- Stop the flow of ozonated water
- Where high levels of ozone are experienced (in excess of 0.1ppm) all personnel should vacate the affected area until it has been thoroughly ventilated
- When ozone levels in excess of 0.3ppm are present, or when personnel are required to work in restricted spaces or tanks, where ozone my be present, only persons wearing suitable breathing apparatus should be allowed in the area and the appropriate safe working practices for confined areas should be applied
|Disposal of waste ozone gas||It is accepted practice, and required by statute in some jurisdictions, that Ozone gas should not be released into the atmosphere but should be destroyed using an approved ozone destruction method. (Catalytic, thermal, or absorption).|
|Disposal of waste ozone gas||
All potential outlets of ozone gas into the occupied areas or external atmosphere should be identified.
- All routine operational releases of ozone to the occupied areas or external atmosphere should be contained and passed through an ozone destruction system (as above)
- All occupied areas where ozone is generated or applied should be provide with an effective ventilation system commensurate with the rate of ozone production and other risk factors
- Where ozone is applied to liquids It is important to consider that ozone will escape from solutions under most conditions. Precautions include: ensuring that all vessels containing ozonated liquids are air-tight or under negative pressure to prevent escape of ozone. Any vents where ozone might escape should be connected to an ozone destruction system. Where ozonated liquids, such as used rinse water, are discharged this should be via close pipe work to close drains
|Disposal of waste ozone gas||
- Eye exposure - If ozone gets into the eyes, wash immediately with large amount of water, lifting the upper and lower eye lids occasionally. Seek medical attention as soon as possible
- Breathing - If a person breaths in large amounts of ozone, move the person into warm un-contaminated air at once. If breathing has stopped, perform artificial respiration. When breathing is difficult, properly trained personnel may assist by administering breathing oxygen. Keep the affected person war and at res. Seek medical attention as soon as possible
- Rescue - Move the affected person to safety. If the person has been overcome notify somebody else and put into effect the established emergency procedures. Do not enter the affected area without assistance or against the advice of the recommended safety procedures as they may apply at each facility