The incident

A saturation diver suffered an injury to his left arm during subsea high-pressure water jetting operations. The incident happeend when the water jet gun failed, and a part came off the gun.

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The diver was recovered to the bell and the water jet gun to the surface. He received first aid and further treatment later in the chamber. He was decompressed and transferred to hospital. Though an LTI, the injury was not severe, and it was expected that the diver would return to his duties within months.

Probable cause

A mixture of causes led to this accident. Equipment failure, improper training and maintenance all played a significant role. Specifically:

  • Locking bolts on the water jet retro came loose;
  • Unsafe design or construction: locking nuts did not have a holding mechanism besides the threads available;
  • Improper worker training/familiarization: manufacturer manuals provided were not available at worksite. There was no awareness of the need for a planned maintenance system (PMS) for high pressure equipment of this sort;
  • Improper maintenance: it was observed during investigation that maintenance was not carried out in accordance to manufacturer’s recommendations.

Lessons learned

However, valuable lessons can be extracted from this incident, such as:

  • Management of change (MoC) needs to be prepared for required changes;
  • Ensure equipment is maintained in accordance with Code of practice for the use of high pressure jetting equipment by divers (IMCA D 049) and any manufacturer’s recommendations;
  • Additional controls put in place to ensure the water jetting equipment is in safe condition, including checking condition of diffuser and locking nuts;
  • Further awareness briefing given to dive team regarding checks of the equipment as per the manufacturer’s recommendations.