202632 Fumigation disaster
Fatal phosphine gas poisoning during underway fumigation
A bulk carrier had been loaded with a cargo of cassava chips. Before departure, shore-based fumigators placed aluminium phosphide tablets on top of the cargo in each hold. The hatches were closed and the crew sealed the hatch coamings with tape before departure. The fumigation personnel provided a written handover to the Chief Officer, but apparently did not explain the risks associated with the fumigation to the crew.
Roughly 36 hours after departure, with the wind astern and the vessel’s speed slightly exceeding wind speed, gas escaping through the hatch and access covers began accumulating on the forward deck instead of dispersing. The accommodation air conditioning was running in recirculation mode, putting the accommodation under negative pressure. Several weathertight doors could not fully close, so contaminated air was drawn into the accommodation and recirculated through every space served by the system. The crew were unaware of these conditions.
Watchkeepers in the wheelhouse, which had the highest air-change rate, fell ill first, suffering from chest tightness, nausea, vomiting, breathlessness and fatigue. Crew and even the Master initially attributed this to food poisoning or Covid-19. Repeated negative antigen tests reinforced the food-poisoning theory. As symptoms spread through the crew over several hours, no one connected the symptoms to the fumigant gas.
At one point, the Master felt ill too. He asked the Chief Mate to relieve him on the bridge as he felt too weak to continue the bridge watch. When the Chief Engineer visited the Master in his cabin sometime later, he found him vomiting severely and his clothes soaked in sweat. The Chief Engineer telephoned the company’s Marine Superintendent to report that 17 crew members, including the Master, were experiencing persistent vomiting and limb weakness.
The Chief Engineer and another crew stopped the vessel and anchored, awaiting search and rescue (SAR) resources. By the time the rescue services arrived at the vessel, about 12 hours after the Master had started to feel unwell, he had passed away. In all, thirteen of the 21 crew died from illness. Forensic findings confirmed toxic pulmonary oedema consistent with phosphine poisoning.
The investigation subsequently found, among other things, that the vessel’s crew were not familiar with the IMO’s Recommendations on the Safe Use of Pesticides on Board Ships. Also, the vessel was not equipped with phosphine gas detection equipment, nor did the crew conduct safety inspections or concentration monitoring of phosphine gas after departure.
Lessons learned
- Underway fumigation with aluminium phosphide is inherently hazardous. Vessels undertaking it must carry phosphine gas detection equipment, and gas concentrations should be checked regularly throughout the voyage – not just at loading.
- Recirculation-mode air conditioning can pull contaminated outside air into an entire accommodation block if door and hatch seals are imperfect. The weathertight integrity of accommodation doors deserves the same attention as hatch covers.
- Wind direction and relative vessel speed affect whether fumigant gas escaping from holds disperses or accumulates near the accommodation. Route and speed planning after fumigation should account for this.
- Symptoms of phosphine poisoning (nausea, vomiting, chest tightness, breathlessness) overlap with seasickness, food poisoning and viral illness.
- Fumigation contractors and ships’ officers should ensure the crew receive a clear safety briefing on the specific risks of the fumigant used – not just paperwork sign-off – and that warning signs are posted at treated holds.
- When carrying fumigated cargo, the vessel’s company should have dedicated safety management procedures for fumigation, including risk assessment, equipment provision and shore support, rather than treating it as a routine cargo operation.
