Diving instructor killed – incorrect valve threads

  • Safety Flash
  • Published on 18 January 2023
  • Generated on 13 December 2024
  • IMCA SF 03/23
  • 1 minute read

The Dutch Labour Inspectorate (Nederlandse Arbeidesinspectie) reports an incident in which a diving instructor was killed. The incident is reported here (in Dutch).

During a dive, the valve came loose from the diving cylinder and fatally  hit the diving instructor; a cylinder with internal thread G3/4 was used,  which was fitted with a valve with external thread M25x2

Diving instructor was killed at work

Threads on the diving cylinder and the mounted valve were  incompatible. In this case, the screw thread of the valve was slightly  smaller than that of the screw thread in the diving cylinder. The result  was that there was an increased risk that the valve will come loose from  the cylinder when at pressure.

Diving cylinder

Threads on the diving cylinder and the mounted valve were  incompatible. In this case, the screw thread of the valve was slightly  smaller than that of the screw thread in the diving cylinder. The result  was that there was an increased risk that the valve will come loose from  the cylinder when at pressure.

Diving cylinder valve

What happened?

During a dive, the valve came loose from the diving cylinder and fatally hit the diving instructor; a cylinder with internal thread G3/4 was used, which was fitted with a valve with external thread M25x2.

What was the cause?

Threads on the diving cylinder and the mounted valve were incompatible.

In this case, the screw thread of the valve was slightly smaller than that of the screw thread in the diving cylinder. 

The result was that there was an increased risk that the valve will come loose from the cylinder when at pressure.

Lessons learned

Members are advised to follow the guidance contained within IMCA D064 Guidance on diving cylinder and valve thread compatibility. 

The Dutch Labour Inspectorate (Nederlandse Arbeidesinspectie) notes that despite various (international) publications about the prevention of such incidents, these situations unfortunately continue to occur.

Latest Safety Flashes:

LTI: Finger injury during emergency recovery of ROV

A worker suffered a serious finger injury when their finger was caught between a crane wire and the recovery hook on an ROV.

Read more
BSEE: recurring hand injuries from alternative cutting devices

The United States Bureau of Safety and Environmental Enforcement (BSEE) has published Safety Alert 487.

Read more
NTSB: Crane wire failure

The National Transportation Safety Board of the United States (NTSB) published "Safer Seas Digest 2023".

Read more
Hot work performed outside of Permit to Work (PTW) boundary limit

A near miss occurred when a third-party contractor working removed a trip hazard from the vessel main deck, using a cutting torch and grinding disc.

Read more
Vital safety information (height of vehicle) found incorrect

“Height of vehicle” information displayed on a truck, was found to be incorrect.

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.