A catastrophic aluminium-alloy dust explosion in China

• Features of a recent catastrophic dust explosion in China are presented and analysed in detail.
• The most likely ignition source was auto-ignition of moistened Al–alloy dust in a dust collecting barrel.
• Important practical lessons have been learnt from this catastrophe.

On August 2, 2014 a catastrophic dust explosion occurred in a large industrial plant for polishing various aluminium-alloy parts in Kunshan, China. The explosion occurred during manual polishing of the surfaces of aluminium-alloy wheel hubs for the car industry. 75 people lost their lives immediately and another 185 were injured. Subsequently, 71 of the seriously injured also died, which increased the total loss of lives to 146. The direct economic loss of was 351 million yuan. This is probably one of the most serious dust explosion catastrophes known apart from some very major coal dust explosion disasters in coal mines.Based on measurements of explosion parameters of dust samples collected on the explosion site and on-site investigations and interviews, it was concluded that a series of consecutive explosions was initiated in one of the external dust filters. Then it propagated into the main building via the dust extraction ducting and further onto the second floor. At the same time the propagating in-house dust flame was sucked into the ducts leading to seven other external dust filters, which also exploded.On the basis of investigations on site after the explosion and subsequent laboratory experiments and data analyses it was concluded that the explosion was most probably initiated by self-ignition of contaminated aluminium-alloy dust in the dust collecting barrel below the external bag filter unit in which the initial primary explosion took place.General ignorance of the potential risk of dust explosions in industries producing fine metal dusts as a low-mass waste by-product is the most probable basic root cause of this catastrophic accident. Therefore, avoiding accumulation of deposits of such dusts indoors by good regular housekeeping and other means is regarded the most effective and practical way of loss prevention due to metal dust explosions in such plants. In addition, explosion isolation between dust collecting systems and workshops appears to be another important measure towards minimizing the consequences of such explosions.