Marine Safety Forum – Safety Flash 07-25
Issued: 8th October 2007
Subject: Shore Worker Dies in On Board ‘Base Oil’ Fire
This safety alert has been issued by the UK Marine Accident Investigation Branch (MAIB)
in their recent Safety Digest 2/07 and is reprinted here with their permission.
An offshore supply vessel was in port for tank cleaning of its mud and base oil tanks prior
to taking on board a fresh cargo. The base oil was a combustible liquid with a flash point of
75°C. A specialist tank cleaning team had been organised and arrived with the tank
cleaning, vacuum and storage equipment required for the work. Prior to commencing, a
cargo surveyor outlined the work required and one of the team arranged a work permit
with the authorising ship’s officer.
Tank entry for the tank cleaners and the suction hose was through a manhole located in
the engine room at an upper level.
After oxygen levels had been checked, three members of the team entered the base oil
tank with the suction hose while other members operated the vacuum equipment ashore.
When all of the base oil had been sucked out of the tank, one of the tank team climbed out
and the three started to remove the hose from the tank. One of the hose connections
became jammed and a second member climbed out of the tank to assist. He subsequently
went ashore to the storage tanker. To facilitate the hose removal, the hose-end section in
the engine room was removed.
The team members who were ashore with the vacuum and storage equipment stopped the
pumping operation ashore and closed the storage tanker valves. A misunderstanding
about the correct sequence of operations apparently occurred and this allowed the
residual vacuum in the suction hose to be lost.
With the hose partially disconnected in the engine room, the base oil remaining in the hose
flowed out under gravity and splashed over the running engine. The base oil ignited and a
sheet of flame and dense smoke enveloped the area.
The tank cleaner who had disconnected the hose in the engine room and a ship’s crew
member escaped out to the deck and raised the alarm. The fire brigade found the body of
the remaining tank cleaner who had still been in the base oil tank when the fire started at
the bottom of the engine room stairs.
An investigation of the accident concluded that the parties involved failed to have a safe
system of work in place. A poor appreciation by all involved of the risks of transferring
base oil was also apparent. The Permit to Work system was not fully understood and the
permit issued was inadequate for the planned activity.
1. Whenever shore contractors are on board your vessel, assure yourself that they are
working safely, are aware of on board hazards in their vicinity and have suitable
measures in place should an incident occur. Deploy a member of the ship’s crew to
assist or stand by while work is in progress and who can halt the work if safety is being
2. As with any visitors on board, contractors should be instructed on emergency
procedures, what to do in the event of an alarm and where escape routes are in
relation to where they are working. They don’t want to be trying to read the escape
notices when surrounded by thick, noxious smoke.
3. When transferring flammable liquids by hose such as fuel oil, lubricating oil, hydraulic
or base oil, be aware of the hazards. A simple risk assessment is a good idea. Before
disconnecting hoses, ensure that the liquid transfer system is properly isolated and the
lines fully drained – trying to stem the flow of a noxious liquid from an open hose while
it splashes over you and surrounding machinery is an unforgettable experience!
4. Ensure that Permits to Work are:
• Explicit in their description of the exact nature, identity and extent of the job, the
names of those detailed for the task, the hazards involved and any limitations on the
extent of the work and time constraints.
• Specific in the precautions to be taken, including a risk assessment, isolation of
potential risks such as running machinery or hazardous substances and using
correct equipment and clothing.
• Checked by an authorising officer who has ensured that the measures specified
have been complied with and who retains responsibility until the permit has been
formally cancelled or responsibility has been transferred to another responsible
• Countersigned by the person undertaking the task to indicate their understanding of
the safety precautions involved.
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Marine Safety Forum – Safety Flash 07-25