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Anhydrous ammonia

Anhydrous ammonia is a colourless gas that has a strong smell and is toxic, corrosive and flammable.

It serves as an effective industrial refrigerant gas, which presents unique challenges to safely manage.

Anhydrous ammonia:

  • is a colourless gas that has a strong smell, and is toxic, corrosive and flammable
  • is an efficient refrigerant having the ability to absorb large quantities of heat
  • is a naturally occurring gas which does not support global warming, nor attack the ozone layer
  • can exist as a liquid, gas or aerosol.

Anhydrous ammonia is generally safe provided safe storage, handling, operating, and maintenance procedures are in place and being followed.

Where is it found?

Anhydrous ammonia is used mainly as an agricultural fertiliser, industrial refrigerant and in the manufacture of ammonium nitrate based fertilisers and explosives. As a refrigerant, it can be found at ice works, cold stores and various food processing facilities (e.g. meat, dairy, processed foods and drinks).

Health effects

Anhydrous ammonia can be harmful, with exposure to 300 ppm being immediately dangerous to life and health.

The effects of breathing in anhydrous ammonia range from lung irritation to severe respiratory injuries, with possible fatality at higher concentrations. Anhydrous ammonia is also corrosive to the skin, eyes and lungs. Liquefied anhydrous ammonia is stored as a liquid and has a boiling point of -33°C. At this temperature it can cause freezing burns.

Emergency planning

Workplaces with ammonia-based refrigeration systems must have a documented emergency plan in place to mitigate the effects on people and the environment in the event of a release of anhydrous ammonia into the atmosphere. Also, the plan is evidence that the person in control of the workplace complies with work health and safety laws.

An Occupier's Guide to Emergency Planning (PDF, 0.65 MB) can assist occupiers to prepare and implement an emergency plan for ammonia-based refrigeration systems. The guide should be read in conjunction with Emergency Planning: A Guideline for Hazardous Industry (PDF, 4.56 MB), that provides emergency planning guidance for all hazardous industries.

Read more about emergency planning for hazardous chemicals.


In 2010, a Workplace Health and Safety Queensland (WHSQ) Safety tool for ammonia refrigeration safety (which included an audit checklist and supporting reference material) was made available to industry. The tool was designed to raise awareness of the hazards and risk control measures and provides additional educational and training material about ammonia safety in the industrial refrigeration industry.

Technical guidance

Technical guidance for ammonia-based refrigeration systems is available in various Australian Standards including:

  • AS/NZS 3788:2006: Pressure equipment – In-service inspection
  • AS/NZS 3873:2001: Pressure equipment – Operation and maintenance
  • The Victorian Code of Practice Ammonia Refrigeration 2010