Diver fatality during subsea lifting operations

Note: This incident is still under investigation.

What happened?

During the removal of a spool at 172msw, divers were engaged in lift bag operations to relocate the spool to a wet store location. During the operation a series of events occurred, which resulted in one end of the spool rising off the seabed in an uncontrolled manner. The umbilical of one of the divers was caught in the lift bag rigging causing the diver to ascend with the spool until the spool’s ascent was arrested.

Subsequent events resulted in the diver’s umbilical being trapped between the spool and a seabed structure, which resulted in the diver losing his primary breathing gas supply. His secondary life support (SLS) was deployed and seems to have operated correctly, however this did not prevent the fatality.

Detailed and exhaustive investigations into the cause of the incident are ongoing in collaboration with the relevant authorities and the client.

Our member made the following interim recommendations:

All diving activities should be risk assessed and planned. The risk assessment and planning should include all key personnel involved in the work to be undertaken. Plans (methodology/working instructions) should be documented, unambiguous, authorised and communicated to everyone involved.

All aspects of the diving operations should be properly supervised. This includes ensuring that the risks involved, work to be done and emergency procedures are communicated to the divers before starting work at the dive site and thereafter, before each dive.

Ensure that the dive site is continuously monitored for changes to the task or conditions. If new hazards are identified or control measures are inadequate, work should be stopped, and the situation reassessed and, if necessary, amended, before starting again.

Review and reinforce individual and collective responsibilities with regard to the management of equipment safety lines/tie backs, lift bags (parachutes) and diver umbilical and every individual’s duty to apply the ‘stop work policy’.

Members should be aware that Guidance on open parachute type underwater air lift bags addresses the operational use of open parachute type underwater air lift bags and the safety precautions that should be taken during their use.

Members may also wish to review Guidelines for management of change.

Further incidents involving lift bags can be found on the IMCA website.

Members may wish to refer to the following incidents:

• Incident during lift bag operations (February 2003)
• Uncontrolled ascent – loss of lift bag to surface (May 2010)
• Uncontrolled ascent of lift bag (June 2012)
• Near miss: Failure of subsea lifting equipment (July 2017)