Fatal HW Explosion on Aqua Ammonia Storage Tank

Many thanks to my friend in safety down under, Mr. Peter Hunt, Director and Principal Consultant, Whamcorp Pty Ltd

On 25 March 1991, a contractor died after an ammonia tank he was upgrading exploded at the ICI plant.

BACKGROUND

  • Contractors oxy-cutting nozzles on aqueous ammonia tanks
  • Tanks were not washed out and cleared and ready for contractors
  • The ammonia/air mixture in the top of the tank was in the critical 16-25 % range of flammability
  • The tank became over-pressured, and the top blew off, fatally injuring the contractor

UNDERLYING CAUSES

  • Inadequate preparation for hot work due to lack of appreciation of properties of ammonia/air mixtures
  • Lack of understanding of the Company’s safety standards
  • Lack of appreciation of the 11one-off 11 nature of the planned work
  • Lack of appreciation of the extent of noncompliance with company standards when New Zealand operation acquired
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