Risks of in-transit fumigation - phosphine gas explosions

Phosphine Gas Explosions

A potential hazard during in-transit fumigation with aluminium phosphide, caused by the inflammability of phosphine and the risk of self-ignition, leading to explosions.

Generation of Phosphine Gas

The process where aluminium phosphide reacts with moisture to produce phosphine gas, with recommended dosages set by organizations like FAO and Degesch for effective fumigation.

Accumulation of Phosphine Gas

The build-up of phosphine gas in the headspace of cargo holds during fumigation, before dispersing into the cargo, following distinct phases of gas generation, diffusion, insect exposure, and ventilation.

Inflammability of Phosphine

Phosphine and diphosphine are highly reactive and unstable chemicals prone to self-ignition, with diphosphine formation contributing to the spontaneous inflammability of phosphine, potentially leading to explosions.

Potential Sources of Ignition

Various factors like hot work, high temperatures, inadvertent wetting of fumigant tablets, static electricity, and diphosphine production can ignite phosphine gas, causing explosions during fumigation.

Safety Precautions

Recommendations to minimize the risk of fumigant explosions include limiting crew exposure near hatch covers in the initial fumigation period, allowing time for the reaction to release phosphine gas and reduce its concentration in the hold.