The Australian Transport Safety Bureau (ATSB) investigated an incident involving crew injuries during maintenance on an oil tanker about 60 km east of Sydney, New South Wales, on 6 May 2025. The report examines the sequence of events, underlying causes, and safety actions taken.
What Happened
While the vessel was drifting offshore, engineering crew began maintenance on a leaking main deck steam valve connected to the cargo heating system. After isolating the system, the team removed the valve bonnet. During this process, residual hot condensate was unexpectedly released, resulting in burn injuries to three crew members. Immediate first aid was provided on board, and the injured personnel were later evacuated ashore for hospital treatment.
Why It Happened
The incident occurred because the crew did not allow sufficient time for the steam system to cool before beginning work. Verification procedures to ensure the line was fully depressurised were not properly followed, with reliance placed solely on pressure gauge readings. Complicating the situation, an undocumented modification had been made to a drain line, altering its original design. This change was neither subjected to a risk assessment nor reviewed or approved, compromising the effectiveness of system isolation. The modification went undetected during routine inspections and was not noted in the chief engineer’s handover process, leaving subsequent crews unaware of the altered configuration. Additional time pressure to restore steam heating for the main engine fuel system contributed further to the incomplete isolation and verification process.
Actions Taken
The modified drain line was restored to its original design configuration. A fleetwide campaign was launched to identify and rectify any unauthorised modifications to shipboard piping systems, and internal investigations will be carried out wherever such modifications are found. Awareness of risks linked to undocumented engineering changes will be reinforced through senior engineering staff briefings and crew seminars. Crew members will be reminded to follow the formal management of change process for all modifications, and superintendent inspection procedures will be updated to include verification of system modifications against design drawings.
Lessons Learned
- Always allow sufficient cooling time before performing maintenance on steam systems.
- Verification of depressurisation should include visual confirmation and not rely solely on pressure gauges.
- Any modification to shipboard systems must be documented, reviewed, and approved through a formal management of change process.
- Engineering handovers should clearly communicate all system changes, temporary or permanent.
- Regular technical inspections must be thorough enough to detect undocumented modifications.
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Source: ATSB
