Skip to content

Near miss/positive: Internal O-ring seal found damaged on fuel system

What happened?

In a vessel alongside, a new fuel gas cylinder was connected to a gas-powered forklift truck. When the delivery valve was opened gas leaked from the connection between the cylinder and the hose. The cylinder was removed and the internal O-ring seal was found to be damaged.

A replacement cylinder was brought to the forklift but before fitting it the crew member checked the condition of the O-ring and found that it too was damaged. Fortunately, a number of full spares are carried on board and one was found that was in good condition.

The two cylinders with faulty O-rings were returned to the supplier for fitment of the correct O-rings. The branch manager of the gas supply company was alerted to the incident. He was most concerned that the cylinders were delivered to a customer without proper examination of the O-rings. They took this as a serious quality control issue and apologised for the occurrence, eventually tracing the batch of refills to a particular time, place and person.

What went right?

  • Supplier was able to remedy a quality control issue;
  • The two faulty cylinders were exchanged before the vessel sailed (after which time return and exchange would not be possible and cargo operations could have been jeopardised).
  • Crew became aware that the fact that the gas cylinder was full did not guarantee it was in proper safe condition. They checked.


  • Closely examine exchanged or pre-used equipment for proper condition, especially where potentially hazardous materials or stored energy is concerned. It always pays to check.
  • O-ring seals are small but vitally important components which should be treated with the greatest of respect.

Members may wish to refer to

Safety Event

Published: 14 August 2020
Download: IMCA SF 24/20

Relevant life-saving rules:
IMCA Safety Flashes
Submit a Report

IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of all. The effectiveness of the IMCA Safety Flash system depends on Members sharing information and so avoiding repeat incidents. Please consider adding [email protected] to your internal distribution list for safety alerts or manually submitting information on incidents you consider may be relevant. All information is anonymised or sanitised, as appropriate.

IMCA’s store terms and conditions ( apply to all downloads from IMCA’s website, including this document.

IMCA makes every effort to ensure the accuracy and reliability of the data contained in the documents it publishes, but IMCA shall 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.