Isolation of fuel tanks
- Safety Flash
- Published on 30 April 2006
- Generated on 30 September 2025
- IMCA SF 05/06
- 2 minute read
IMCA has been advised of a near-miss accident that occurred during a fuel transfer operation.
What happened?
Whilst the vessel was in dry dock, fuel was accidentally transferred into a tank in which hot work was planned. As a result, around 7mâ³ of marine diesel oil was spilled onto the dock via an opening in the tank and the hull of the vessel. No people were working on the dock at the time, nor were there personnel inside or in the vicinity of the tank.
The situation occurred with a lock-out/tag-out procedure and a permit to work both in place. Such systems should have functioned as barriers against the unintended flow of fuel in an open tank.
Recommendations
After investigation of the incident, the company decided to change the isolation requirements for entry into a fuel tank. It made the following recommendations:
- When access to a fuel tank is required for maintenance or cleaning activities, all fuel inlets should be blind flanged.
- Isolation by means of blind flanges should be reflected on the permit to work.
- Isolation tags should be logged, using the drawings of the fuel system as guidance.
- Information on the status of open tanks should be known in the engine control room and on the bridge.
- All isolation points for each tank should be identified and known.
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.