At least two died and hundreds were injured in Taiwan when clouds of multi-coloured corn starch sprayed on the crowds exploded and engulfed the young revellers in flames ("S'porean among nearly 500 injured in Taiwan festival fire"; Monday, and "Colour Run to continue in S'pore"; Thursday).
The cause is likely to be cigarette lighters or heat from stage lights. The manufacturer had marked the powder as "flammable", but the organisers ignored the warning. They said they had never heard that such an activity could be dangerous.
Likewise, most housewives cannot imagine that a bag of corn flour in the kitchen can explode, the way it did in Taiwan.
Last August, metallic dust suspended in factory air exploded in China, killing at least 75 and injuring many more ("Safety breaches at auto factory led to deadly dust blast, says Xinhua"; Aug 5, 2014). The factory polishes hubcaps. Perhaps the heat source was also a cigarette lighter.
Experts have said that dust can be highly explosive when it is suspended in air, in the right concentrations, and this is true even of materials such as aluminium and iron that typically do not burn.
We need to learn from these incidents. We must bear in mind that a heat source need not be external; dust particles rubbing against one another at high speeds can also result in a spark or explosion.
Kevin Ho Kun Kok