Near miss: Foreign body in diver’s helmet, resulting in fall of gas pressure
- Safety Flash
- Published on 27 February 2023
- Generated on 18 August 2025
- IMCA SF 06/23
- 2 minute read
During a routine dive at a depth of 18m (60’), the diver reported to the Dive Supervisor a drop in breathing gas pressure.
What happened?
The diver switched to bailout gas which did not solve the problem.
The diver opened the free flow which increased gas pressure to a suitable level.
The diver left the sea bottom and returned safely to the vessel deck.
Upon removal of the diving helmet (a Kirby Morgan 37) a foreign body was found in the demand valve chamber section of the helmet regulator.
What went right?
The diver remained composed and took the correct emergency actions.
What went wrong?
A foreign body found its way undetected into the helmet during pre/post-dive cleaning. It is thought that the likely cause was the foreign body – a small shard of plastic – entered the regulator body and restricted the action of the lever arm.
- The bowl or utensil used for cleaning helmet parts was an old and broken plastic pot.
- The foreign body was identified as being part of the old and broken plastic pot used as a cleaning utensil.
Plastic pot used to wash the internals of the hat
Foreign body from the plastic pot broken off (22 mm)
What was the cause?
Inappropriate or sub-standard cleaning technique for an item as vital as a diver’s helmet
Lessons and actions
- Consider how something so minor could have such an impact on a diver’s gas supply.
- Reiterate the importance of pre-dive checks and of the need for absolute cleanliness in divers’ life-saving equipment.
- Our member introduced spray bottles to eliminate the chance of particles entering the helmet during cleaning.
Related safety flashes
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IMCA SF 06/22
11 March 2022
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IMCA SF 30/21
8 November 2021
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IMCA SF 26/21
22 September 2021
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IMCA SF 12/18
14 June 2018
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