Lack of Knowledge Led to Enclosed Space Death
The Accident Investigation Board Norway (AIBN) has released its report on death of a seafarer in an enclosed space on board the factory trawler Nordstar on June 10, 2018.
The crewmember was preparing to clean a silage tank, and it is likely that he was exposed to immediately lethal levels of gas as he climbed down to the bottom of the tank.
The investigation showed that methane gas as well as toxic hydrogen sulfide gas had probably formed as a result of a decomposition process in the silage tank.
The AIBM concluded that the crew had different understandings of how to prepare for tank cleaning, with respect to both flushing and ventilation of the tank. The crewman, who was wearing a personal oxygen detector, decided to enter the tank to set up the fan, since the oxygen measurement did not show that there was insufficient oxygen inside the tank. The available detector only measured the level of oxygen, not other gases. It was therefore not possible for the crewman to determine whether the atmosphere was safe.
Extensive efforts were required to get the crewman up from the tank, and challenges were encountered relating to the availability of suitable equipment, a lack of hoisting equipment, and getting him up past the ladder cage.
The hazards associated with gas formation were not mentioned in the shipping company's risk assessments, checklists or work procedures. Tanks with contents that represented a potential gas hazard were not sufficiently labelled, and equipment for detecting hazardous gas was lacking, states the AIBN report. This contributed to a situation where personnel carrying out work on storage tanks and those responsible for approving such work were unaware of the potential risks to which they were exposed. The crew also lacked sufficient emergency preparedness training and training in how to rescue people from a tank.
The report is available here.