A routine maintenance job on the fishing vessel Antarctic Discovery became a life-threatening emergency when decomposing fish offal was accidentally pumped into a machinery space, released toxic gas and put four workers in hospital.
The Transport Accident Investigation Commission (TAIC) released its report into the February 2025 accident today. [EDS; 0500, 23 JULY]
On 21 February 2025, the vessel was in dry dock at Lyttelton. Two apprentice fitters descended a ladder to the bow thruster machinery space to work on pipe components tucked behind a tank that held had a mixture of decaying fish offal and seawater. The pipework was immediately adjacent to the control panel for the offal pump. It is about as likely as not that one of the fitters accidentally pressed the pump’s unlabelled start button, and the holding tank’s contents rained onto the fitters from the open end of a hose at the top of the ladder. Foul-smelling toxic hydrogen sulphide gas (a known by-product of decaying fish) began building up. The fitters had no option but to climb the ladder through the falling liquid to escape to the open air.
The vessel superintendent went below to investigate and was briefly overcome by gas. The chief engineer and second engineer also entered the area, collapsed, and were rescued by crew using breathing apparatus. Four workers were hospitalised and later recovered.
Acting Chief Investigator of Accidents Tahlia Fisher says the immediate cause of the accident was the accidental starting of an offal pump, but the investigation found four broader safety issues that affect industries well beyond the marine sector.
“First, it’s essential that before work begins all machinery be made safe – and that includes not just the equipment being worked on, but also nearby systems that could create danger if activated.
“Also, if a space has the hazards or characteristics of an enclosed or confined space, manage it as such, regardless of what it is called. In this case, the bow thruster machinery space had the hazards and characteristics of an enclosed or confined space but hadn’t been recognised and managed as one.
“And where multiple organisations are operating in the same workplace, there will be overlapping responsibilities, and safety depends on active coordination between everyone working on site.
“Finally, a point for senior managers and leaders is that safety-critical modifications need proper oversight with formal approval, documentation and oversight.”
Acknowledging extensive safety actions already taken by Antarctic Discovery’s owner, Australian Longline Pty. Ltd., the Commission made recommendations to Australian Longline and Lyttelton Port Company to strengthen management of safety-critical systems and dry dock operations.
The purpose of every TAIC inquiry is not to ascribe blame, but to help the transport sector improve safety by avoiding repeat accidents. The Commission opens an inquiry when it believes the circumstances have - or are likely to have - significant implications for transport safety, or when the inquiry may allow the Commission to make findings or recommendations to improve transport safety.