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 generally safe provided safe storage, handling, operating, and maintenance procedures are in place and 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.
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 at low exposure levels to severe respiratory injuries, pulmonary oedema and death at higher exposure 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 severe cold (freezing) burns.
Emergency planning
Workplaces with using anhydrous ammonia gas-including in 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.
Refrigeration (ammonia gas) safety resources
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.
The tool is being updated by WHSQ and is temporarily unavailable.
Technical guidance
Technical guidance for ammonia-based refrigeration systems is available in various Australian Standards including:
- AS/NZS 5149:2016: Refrigerating systems and heat pumps (part 1-4) (supersedes AS/NZS 1677)
Guidance note
Anhydrous Ammonia Gas – Safety in agriculture guidance note (PDF, 0.92 MB)
This guidance note draws together key relevant safety information and legislation which should be considered for the safe use of ammonia gas within an agricultural setting in Queensland.