(www.MaritimeCyprus.com) Transport Malta's Marine Safety Investigation Unit (MSIU) has released a report on a fatal incident aboard the Maltese-registered oil tanker SEAPRINCESS at the TK Tuzla Shipyard in Turkey, on 14 August 2023.
The SEAPRINCESS arrived at the shipyard for planned dry-docking on 29 July 2023. Upon its arrival, all cargo and slop tanks had been washed, cleaned, dried, and declared gas-free. Although the compartments were tested daily and deemed gas-free, entry was only permitted with a personal gas monitor, and the environment was still unsafe for hot work.
On 14 August, two welders from the repair riding team were tasked with repairing damaged stanchions in the port-side slop tank, identified during a survey on 6 August. After setting up the welding equipment, one of the welders, just beginning to weld, noticed a fireball rising from the bottom of the tank, followed by a sudden rush of air. He shouted for his colleague to escape to the nearby ladder. The force of the explosion propelled him 12 meters into the air, and a second explosion cushioned his fall to the deck. A small fire inside the tank was quickly extinguished. After the tank was declared safe, the second welder’s body was recovered.
Although the slop tank had been tested and declared gas-free earlier that morning, the investigation concluded that a small gas pocket likely formed at the lower levels of the tank and went undetected, causing the explosion.
No evidence suggested that fatigue or alcohol contributed to the accident, though rest hours were not documented for the welders, and no alcohol tests were conducted following the incident. The investigation did not identify any behavior indicating fatigue as a factor. The report aims to prevent future marine casualties by identifying the circumstances and safety issues surrounding the accident.
INVESTIGATION REPORT FINDINGSNote: Findings and safety factors are not listed in any order of priority. Immediate Cause of the Accident Welding splatters ignited undetected hydrocarbon vapour present inside the port side slop tank. Conditions and other Safety Factors - A quantity of oily-water mixture, which unknowingly had remained inside the decanting line between the two slop tanks, was released inside the port side
slop tank. - This oily-water mixture eventually released hydrocarbon vapour inside the tank.
- Ensuring that all interconnecting pipelines were flushed was a significant, daunting task and missing on interconnections comes as no surprise.
- The more the crew members, contractors and shipyard workers are engaged in the numerous, simultaneous tasks which need to be carried out whilst the vessel is in the shipyard, the more complex the situation becomes.
- Although the slop tank had been tested at 0800 and was found to be gas free, the safety investigation concluded that the build-up of a small gas pocket at the lower levels of the tank escaped detection when the atmosphere was tested by the shipyard that morning.
- It was possible that the two welders were either unaware that the slop tank was not cleared for hot work, or they had missed the warning sign altogether.
- Although the vessel’s procedures required all interconnecting pipelines between compartments to be flushed through and vented, this did not occur.
- The safety investigation identified instances where communication may have been an issue. The OOW, senior officers and the superintendents were all unaware that entry into the port slop tank and hot work was being contemplated that morning by the riding team.
- Considering the timing of the completion of the safety round checklist, even if the duty officer conducted his safety round in accordance with the checklist, he would have been unaware of the work that was about to take place at around 0900 – unless he was told about it, or he happened to be in the vicinity of the entrance.
- The two welders had no cues that a simple welding task would have led to tragic consequences.
- Whilst the safety investigation did not exclude that the two repair team members may have been aware of the oily-mixture leak inside the slope tank, the risk related to such a leak was either not identified, or not appreciated by them.
- Recollections of all those present indicated that this incident had not been reported because the presence of the oily-mixture only became known after the explosion happened.
- The safety investigation believes that the entry into the enclosed space, and the eventual commencement of the hot work, was a situational performance variability, ‘instigated’ and consequential of the prevailing complex, operational context, which one would typically find in a shipyard.
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For more details, download below the full Investigation Report from MSIU:
