AMMONIA LEAK FROM REFRIGERATION SYSTEM

Incident
Approximately 56 kg of anhydrous ammonia was released to the atmosphere from
a 25-year-old refrigeration system. The emergency services stopped the leak by
closing an isolating valve. There was no injury. The site was not licensed for the
storage of anhydrous ammonia.
Causes
One valve failed to close and stop filling up the accumulator of the refrigerating
system. This resulted in flooding of the refrigeration compressor by liquefied
anhydrous ammonia, causing one of the compressor O-rings to fail, thereby causing
the release of anhydrous ammonia to the atmosphere. This points to an inadequate
maintenance program.
Consequences
The operator has been instructed to take appropriate measures so that the
refrigerating system complies with the relevant safety standard and the Dangerous
Goods Regulations. The operator was successfully prosecuted for failing to placard
the site and have a licence to store anhydrous ammonia.

Source: Department of Minerals and Energy, Australia