The explosive potential of custard powder

Custard powder is a common ingredient in many kitchens, known for its ability to create delicious desserts with just the addition of water and heat. However, this seemingly innocent powder has a hidden danger that many people may not be aware of. On November 18, 1981, a serious incident occurred at the Bird's Custard factory in Oxfordshire, where a large amount of custard powder spilled out of a hopper, creating a dust cloud that ignited and exploded. This explosion injured nine workers, and they were fortunate to escape with their lives, as dust explosions can often be fatal. In fact, there have been numerous incidents over the years where similar explosions have resulted in tragic outcomes, including a flour mill explosion that claimed the lives of fourteen people and another incident that devastated a town, resulting in many injuries. One eyewitness described the explosion as, 'The main explosion seemed to lift great buildings and hold them in tension for a moment, letting them drop with their own weight. ' Dust explosions have continued to pose a threat, with incidents reported in 2014 and 2022, although not all of these involved food products. Custard powder is made from cornstarch, which is used instead of eggs to thicken the mixture. Its popularity has grown due to its portability and long shelf life. But how can a simple dessert ingredient lead to such catastrophic events? The answer lies in the nature of dust explosions. For an explosion to occur, the powder must be made from a flammable substance. While materials like sand are safe because they are composed of minerals, substances such as flour, cornstarch, sugar, coal dust, and even powdered plastics can ignite if they become airborne. When these particles are suspended in the air, they have a much larger surface area exposed to oxygen, which increases the likelihood of combustion. If just a few particles heat up to their ignition point, the fire can spread rapidly throughout the entire dust cloud. This is similar to how a pile of confetti ignites quickly when thrown into a fire. On that fateful day at the Bird's Custard factory, there were 20 workers present. Several of them noticed that cornstarch was overflowing from one of the bins. Witnesses reported seeing a flash of light near the top of the bin, followed by a wall of flames spreading outward. The report described the scene as, 'Descriptions were of a gale-force wind with a flame front behind, which flashed through the area. ' Investigations later revealed that the machinery responsible for dispensing the cornstarch had malfunctioned, causing it to overflow and create a dangerous situation. To prevent such explosions, it is essential to address the issue from multiple angles. Factories must implement safety measures such as grounding all machinery to reduce static electricity, installing filtration systems to remove dust from the air, and conducting regular inspections to identify and eliminate dust build-up. Modern equipment in facilities like flour mills must be properly grounded to prevent static electricity that could ignite an explosion. When you look at a spoonful of cornstarch or custard powder, it is difficult to imagine it as a potential source of destruction. Most people have never experienced a dust explosion firsthand, making it challenging to view these substances as hazardous. However, there are situations where this dangerous chemistry can be encountered outside of industrial settings. For example, at parties where colored powders, often made from cornstarch, are thrown into the air, there is a risk of creating explosive conditions. In 2015, a tragic incident at a water park in Taiwan involved colored powder, resulting in over 500 injuries and 20 fatalities. The management of the park claimed they were unaware that such explosive fires could occur due to cornstarch clouds. In fact, many colored powders are sold with labels incorrectly stating that they are non-flammable, a fact that scientists have confirmed through testing. Fortunately, during the incident at Bird's Custard, the flames did not disturb any dust that could have triggered a secondary explosion. However, it is not uncommon for dust explosions to escalate when lingering dust is stirred up and becomes airborne. The only way to prevent these disasters is through proactive measures, such as maintaining cleanliness in areas where powders are used, monitoring for heat sources, and, most importantly, recognizing the potential dangers that can lurk within seemingly harmless ingredients like custard powder.