An intense fire caused by the spontaneous ignition of white phosphorus occurred in a storage building of a chemical industry (distillation of white phosphorus). The storage building contained 166 drums of white phosphorus of 200 kg each. The building was a single storey steel frame with brick and concrete infill and asbestos-cement roof.

The failure of the seal allowed storage drum “to breathe” during unusually extreme day/night temperature changes. The unexpected physicochemical reaction of air entering the drum, water and white phosphorus caused the production of phosphoric acid that corroded the drum, releasing liquor and allowing ignition.

4 operators on shift and others were called in to assist in fighting the fire together with a 24 firemen and a chemical emergency response vehicle. Hand held extinguishers and 3/4″ hose reels were used to fight the fire.

As the fume cloud was high, no smoke fume was reported at ground level although some smell was detected in a specific area outside the calculated plume path. Local inhabitants were advised to stay indoors and not to eat vegetables from gardens without first washing them well. The fire caused structural damage to the building.

One drum had caught fire 15 days prior (21/07/1990), affecting 67 other drums nearby. Corrosion had been found inside the affected drums. The second fire occurred before the other drums could be checked. The investigation showed that operating procedures about inspection and material storage were inadequate. The operator took the following measures:

• drum filling method to be clearly specified and suppliers procedures approved;
• tight head lacquer lined drums to be used;
• water in drums to be buffered;
• drums to be stored under water in medium/long term storage;
• if outside, drums to be on pallet 1 metres high;
• if outside, pallets to be 0.6 metres apart;
• if inside, pallets to be no more than 2 high, 2 wide with 6 metres clearance between stacks;
• on receipt, drums to be physically examined, opened and the water pH checked and buffered if low; level to be topped up;
• close circuit TV to be installed.