Dropped wooden block in conductor support frame

  • Safety Flash
  • Published on 17 September 2019
  • Generated on 19 April 2025
  • IMCA SF 22/19
  • 2 minute read

During a decommissioning project, a wooden wedge, weighing approximately 13 kg, dropped 6 m, striking a rigger’s hard hat and shoulder on its way down.

What happened?

The rigger suffered minor cuts; it was fortunate that his injuries were not more serious. The incident occurred during decommissioning operations using a conductor support frame (CSF) to help with the removal of conductors.

Conductors were pulled into position in the CSF by crane. To reduce horizontal movements, wooden wedges were installed, whilst the conductors were being cut in smaller sections. During removal of the wedges, one of the wedges fell and struck the rigger.

During a decommissioning project, a wooden wedge, weighing approximately 13 kg, dropped 6 m, striking a rigger’s hard hat and shoulder on its way down

What went wrong?

As per company procedure, the wedges were to be placed into position at level B, to remove any horizontal movements of the conductor. To reduce movements from the top of the conductor, additional wedges were installed at level D (top level) of the CSF; this addition was not part of any procedure.

After completion of the sectioning cut at level A, the rigging team started to remove the wedges installed at level B, as per original procedure. Whilst removing the wedges at level B, one of the wedges installed at level D dropped to level B striking one of the riggers.

Whilst removing the wedges at level B, one of the wedges installed at level D dropped to level B striking one of the riggers.

The investigation revealed that:

  • Procedures had not been updated to include the additional wedges at level D.

  • Management of change (MoC) was not implemented/followed.

  • There was a failure of the wedge securing eyes due to vertical movement of the conductors caused by vessel/platform movement.

  • It was not identified that removal of the (upper) level D wedges prior to removal of the (lower) level B wedges would have eliminated the dropped object risk.

What actions were taken? What lessons were learned?

  • Any change to a procedure should be subject to MoC.

  • Procedures should be updated immediately and re-issued to include any changes.

  • Any changes to procedures should be communicated to all personnel potentially affected by the change.

  • All persons involved should take part in risk assessments/job safety analysis (JSA) in order to ensure all hazards are identified and eliminated/controlled.

Members may wish to refer to:

Latest Safety Flashes:

Fatality following a fall from a wind turbine

The Scottish Courts and Tribunals Service, and UK HSE, has published a response to a fatal incident in which a crew member fell to their death.

Read more
UK HSE: Risk of collision with offshore installations from attendant vessels

The UK Health and Safety Executive (HSE) has published Safety Notice ED01-2025 relating to the risk of collision with offshore installations.

Read more
USCG: Hazardous Zone Markings and Safety Protocol Awareness

The United States Coastguard has published Safety Alert 04-25 relating to the importance of Hazardous Zone Markings and Safety Protocol Awareness.

Read more
BSEE: Crane safety awareness during offshore helideck operations

BSEE published Safety Alert 491 relating to a the investigation of a near miss crane incident on an offshore platform.

Read more
Incidents occurring during decommissioning

IMCA has put together a summary of incidents relating to decommissioning.

Read more

IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of the entire offshore industry.

The effectiveness of the IMCA Safety Flash system depends on the industry sharing information and so avoiding repeat incidents. Incidents are classified according to IOGP's Life Saving Rules.

All information is anonymised or sanitised, as appropriate, and warnings for graphic content included where possible.

IMCA makes every effort to ensure both the accuracy and reliability of the information shared, but is not be liable for any guidance and/or recommendation and/or statement herein contained.

The information contained in this document does not fulfil or replace any individual's or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.

Share your safety incidents with IMCA online. Sign-up to receive Safety Flashes straight to your email.