Flour Power: An Explosive Danger

Ingredients like sugar and flour are important to the baker but they can also be lethal. HLF Risk Services’s Chris Martin, head of Fire and Safety, outlines the dangers and the remedies.

They are essential for breads, pastries, cakes and other confectionery. We use them, process them and eat them.

So who would have thought that flour, sugar and similar powdered ingredients could have been responsible for more than 300 dust explosions and the resultant deaths of 120 workers in the past three decades?

The fact is that a dust explosion occurs every single week and 24 per cent of all dust explosions occur in the food industry. Another fact is that they can all be prevented. But what happens to turn a seemingly harmless operation involving dried ingredients into a potentially fatal one?

For a dust explosion to occur, five conditions must coexist:
• Combustible dust
• Dispersion
• An oxidiser (such as air)
• Confinement
• Ignition source

These five factors are known as the dust explosion pentagon. Combustible dusts in the food industry include flour, custard powder, instant coffee, sugar, dried milk, potato powder and soup powder – in fact, practically all organic-based dusts, given the right conditions, can explode, with devastating results.

In 1981 at General Foods, Banbury, a dust explosion occurred when pneumatically conveying cornstarch for custard making, a hopper was overfilled. This created a dust cloud which was ignited by nearby electrical equipment, leaving nine men badly burnt.
An explosion occurred in a grain storage complex at Société d’Exploitation Maritime Blayaise in August 1997, killing 11 people in nearby offices. Significantly-sized pieces of debris from the explosion were found up to 100 metres from the silo.

And just last year 13 workers died and 40 were hospitalized following a sugar dust explosion at the Imperial Sugar Refinery in Georgia, USA.