Sequence of errors led to seafarer’s death from hazardous gas inhalation

A large number of flaws in process led to a seafarer on factory trawler Nordstar (IMO 6920111) dying as a result of the inhalation of toxic gas while preparing to clean a silage tank, according to a just-released report from Accident Investigation Board Norway (AIBN).

On June 10th 2018 a crew member died on board the Nordstar. The investigation found that methane gas and toxic hydrogen sulphide gas had probably formed as a result of a decomposition process in the silage tank.

The investigation found that the risk of gas being formed during the production and storage of silage had not been identified as a hazard in the shipping company’s safety management system.

The investigation also found that knowledge of the hazards associated with the formation of gas when fish waste/silage decomposed was not transferred in an effective manner from the other parties in the project to the shipping company; neither were they identified by the shipping company or the supervisory authority (the Norwegian Maritime Authority) during the operating phase of the project.

AIBN found that it was likely that the fisherman was quickly exposed to immediately fatal levels of gas as he climbed down to the bottom of the tank. Retrieving the seafarer from the tank was a complex operation.

AIBN said that 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. This, the investigators found, 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 shipping company concerned had since implemented several measures to prevent a reoccurrence.

The shipping company’s expectations that other parties would assist by providing detailed information about the hazards associated with silage production and work in tanks was not in line with those parties’ own understanding of their role in the project. AIBN said that this resulted in risks associated with the production and storage of silage not being identified or taken into consideration in the plant’s operation.

The NMA’s audit failed to detect that the operational hazards associated with silage production and storage were not mentioned in either the shipping company’s or in the vessel’s safety management system.

AIBN’s conclusions were:

Operational factors:

  1. The crew had different understandings of how to prepare for tank cleaning, with respect to both flushing and ventilation of the tank.
  2. The fisherman, who was wearing a personal oxygen detector, decided to enter the tank to set up the fan, since the O2 measurement did not show that there was insufficient oxygen inside the tank. The fisherman probably knew too little about the risk of hazardous gas being present in the silage tanks.
  3. The available detector only measured the level of oxygen, not other gases. It was therefore not possible for the deceased to determine whether the atmosphere was safe, as the shipping company’s procedures state should be ascertained before entering a tank.
  4. Since no work inside the tank had been agreed in advance, the checklist for entering an enclosed space had not been filled in and reviewed before tank entry.
  5. The fisherman was probably very quickly exposed to toxic hydrogen sulphide gas as he climbed down to the bottom of the tank. This probably lead to immediately fatal exposure.
  6. Extensive efforts were required to get the fisherman up from the tank, and challenges were encountered relating to the availability of suitable equipment, a lack of hoisting equipment, and getting the fisherman up past the ladder cage.

Organizational and systemic factors:

  1. The risk of gas being formed during the production and storage of silage had not been identified as a hazard in the shipping company’s safety management system. The hazards associated with gas formation were not mentioned in risk assessments, checklists or work procedures. 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.
  2. The shipping company lacked a work procedure for silage tank cleaning and guidelines for when tanks were to be cleaned after unloading.
  3. The shipping company had not put up signs warning of a potential gas hazard related to the tank content, and there was no detection equipment for hazardous gases.
  4. The crew lacked sufficient emergency preparedness training and training in how to rescue people from a tank. It was somewhat unclear where the rescue equipment was located; neither was the equipment adapted to enabling the efficient rescue of personnel from a tank.
  5. Knowledge of the hazards associated with the formation of gas when fish waste/silage decomposes was not transferred in an effective manner from the other parties in the pilot project to the shipping company, and nor were they identified by the shipping company or the supervisory authority (the Norwegian Maritime Authority) during the operating phase.
  6. The shipping company’s expectations that other parties would assist by providing detailed information about the hazards associated with silage production and work in tanks was not in agreement with the parties’ own understanding of their role in the project. This resulted in risks associated with the production and storage of silage not being identified or taken into consideration in the plant’s operation.
  7. The NMA’s audit did detect that the operational hazards associated with silage production and storage were not mentioned in either the shipping company’s or in the vessel’s safety management system.

However, The investigation of the accident on board the Nordstar on 10 June 2018 has not identified new areas in which the Accident Investigation Board Norway deems it necessary to propose safety recommendations for the purpose of improving safety at sea.

1696-built, Norway-flagged, 2,053 gt Nordstar is owned and managed by Nordnes AS of Valderoya, Norway. It is entered with Gard P&I (Bermuda) on behalf of Nordnes AS.https://www.aibn.no/Marine/Published-reports/2020-02-eng