Information on Managing Risk While Transporting Fumigated Cargo

This incident information refers to the transportation of fumigated cargoes and how to manage risk resulting from such kind of cargoes. A bulk carrier was carrying a wheat cargo between two ports in Europe. The cargo was fumigated with phosphine gas during the voyage to protect it from insects and rodents. The gas somehow reached the crew’s cabins and a 22-year-old Latvian crew member died from exposure to the gas.

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The vessel arrived in port and the Master reported the fatal accident. One day later, a second seafarer fell ill and for safety reasons the whole crew was evacuated from the ship. The maritime authorities detained the ship and an investigation has been initiated to find the channels through which the gas leaked into the cabins.

Aluminium phosphide tablets are a common pesticide for grain cargoes on board ships and are often stated in the requirements stipulated by the national authorities (in the country where the cargo is unloaded) and/or the cargo owner. Aluminium phosphide reacts with moisture in the air (i.e. water) and liberates a dangerous gas – phosphine. Phosphine gas kills the insects and rodents by decompressing their central nervous system and respiratory function. Phosphine gas is also dangerous to man and may cause coughing, nausea, headaches, pain and tightness in the chest, shortness of breath, vomiting and convulsions. The symptoms of lung oedema often do not become manifest until a few hours have passed and they are aggravated by physical effort. Exposure may also be fatal and in the above accident the seafarer most likely died from phosphine poisoning.

A similar case was reported by the Maritime Accident Investigation Branch (UK) in 2008, in which one seafarer was also killed. In that case, some of the cabins in the superstructure extended over the cargo space by 0.5 m (over the aft bulkhead of the ship’s aft cargo hold as indicated in the photo below). After the under-deck area in the cargo hold had been thoroughly de-scaled, some pin holes were discovered through which the phosphine gas had leaked into the cabins and accommodation areas.

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Another investigation report from the Australian Transport Safety Bureau reports a fire caused by aluminium phosphide tablets used as a fumigant in a seed cake bulk cargo (palm kernel expeller). When the aluminium phosphide reacts with water and liberates phosphine, heat is also produced. It was raining during loading and the fumigator-in-charge decided to bury the aluminium phosphide (socks of tablets) in the cargo in an attempt to protect the fumigant from the rain (and prevent a too rapid chemical reaction). After one day at sea, the crew noted black smoke coming from one of the cargo holds. The fire did not escalate due to some preventive measures by the crew and the hatches were opened with rigorous safety precautions in the next port (14 days later). The fire in the remains of the smouldering cargo was successfully extinguished.

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Phosphine gas is flammable and the aluminium phosphide tablets used to fumigate grain cargoes are understood to be composed of pure aluminium phosphide (active ingredient) and ammonium carbonate (inert ingredient). The ratio of the active ingredient to the inert ingredient is generally about 56:44. In the chemical reaction with moisture, phosphine gas is released along with carbon dioxide and ammonia, which prevent the phosphine gas from self-igniting. Once the tablets have completely decomposed, aluminium hydroxide is left behind as a harmless and nontoxic greyish white residue.

DNV has also another report regarding a bulk carrier, where there were explosions in two of the cargo holds that lifted and severely deformed the hatch covers. No crew members were injured in this incident, but the hatches needed a thorough repair at a shipyard. The bulk carrier was carrying a cargo of wheat and was being fumigated using aluminium phosphide  tablets.

The procedures to be followed when carrying a fumigated cargo are detailed clearly in IMO’s following guidelines

  • IMO MSC.1/Circ.1264 “Recommendations on the safe use of pesticides in ships applicable to the fumigation of cargo holds”. MSC.1/Circ.1264 is also included as an appendix to the IMSBC Code (the International  Maritime Solid Bulk Cargoes Code).
  • IMO MSC.1/Circ.1265 “Recommendations on the safe use of pesticides in ships applicable to the fumigation of cargo transport units”

The recommended procedures include that the fumigator-incharge carries out a thorough pre-fumigation check to ensure the ship is safe to transport a fumigated cargo. This is to be documented in a checklist. The Master must also be aware that the cargo is to be fumigated and have given his permission for it to be loaded and fumigated. Finally, the crew are to be briefed about the dangers that the fumigated cargo may pose and the test regime for leaking gas.

The MLC 2006 (Maritime Labour Convention) calls for safe and decent working and living conditions. There are numerous requirements for inspecting, reporting and correcting unsafe conditions, and for investigating and reporting occupational accidents on board, in the Convention. (e.g. Regulation 4.3 – Health and safety protection and accident prevention).

When the Convention enters into force, it is natural to assume that the ship’s risk- and safety assessment w.r.t. fumigation should be addressed by the MLC inspector as part of the scope during an inspection.

From incidents such as the one analysed above the following should be outlined:

  • Aluminium phosphide tablets, which react with moisture in the air, are often used to fumigate grain cargo. The reaction liberates phosphine (PH3) as the active gas to protect the cargo from insects and rodents. Exposure to large concentrations of phosphine gas can be lethal to human beings.
  • Data sheets for phosphine show that the gas is heavier than air (by about a factor of 1.17) but the cases discussed in this newsletter indicate that the gas has risen into the accommodation, probably due to over-pressure in the cargo holds. Phosphine has been described as having a fishy smell and sometimes as smelling of garlic.
  • A copy of the IMO’s “Recommendations on the safe use of pesticides in ships” should be kept on board vessels which may be required to fumigate cargo holds, and the contents should be well understood by the Master and key officers.
  • Procedures for gas concentration safety checks during a voyage with fumigated cargo should be established and should include all appropriate locations (that share boundaries with the cargo holds), like the accommodation, engine room and frequently visited working areas and stores, such as the forecastle head spaces.
  • The Safety Management System required in the ISM Code should address shipboard operations and emergency preparedness. For vessels whose cargo is fumigated, there must be well established (implemented) procedures that are at least in accordance with the IMO recommendations. This probably includes responsibilities, procedures before/during/after fumigation, gas sampling during the voyage and safety briefings to the crew members.

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Source: DNV

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