592 - 7/08 - Case study: improper use of fumigant in bulk cargoes - Worldwide

Members shipping dry bulk cargoes are alerted to a recent Transport Safety Investigation Report, issued by the Australian Transport Safety Bureau, into a cargo fire caused by the improper application of fumigant to the cargo.

The ship was loading a bulk cargo of palm kernel expeller (PKE), listed in the IMO BC Code as non-hazardous seed cake. Before the cargo hold hatch covers were closed, a fumigation contractor added fumigant to each hold at a rate of two grams of phosphine per cubic metre of cargo.

The plan was to place socks containing aluminium phosphide tablets on the surface of each cargo hold. However, it was raining so the contractor advised the master that the fumigant should not be placed in the cargo holds while it was raining. He outlined how the moisture from the rain could cause the fumigant to react more quickly, possibly causing it to ignite. However, the master instructed the contractor to carry out the task immediately so that the ship's departure was not delayed. As a result, the contractor buried the fumigant in the cargo in an attempt to protect it from the rain.

The cargo hold hatch covers and ventilators were then closed and sealed. The next day the crew observed black smoke coming from one of the cargo holds.

When the hold was opened, it was apparent that only two small areas of the cargo had been affected. Both of the affected areas had burnt in a circular pattern that was centred on the location of a fumigation sock. However, the fires had not grown in size over the ensuing days because as they developed they had consumed the available oxygen in the cargo hold.