How Dust Explosions Happen
Bucket elevators routinely operate in conditions where both Dust and Oxygen are constantly present. Only the condition of the bearings, buckets, belts or chains determine if and when a spark or flame could potentially cause a dust explosion.
The most notable dust explosion to date was that of the Imperial Sugar Company, which took place at the refinery’s Port Wentworth, GA facility in 2008. According to the final report by the U.S. Chemical Safety Board, the dust explosion at this particular sugar refinery was caused by a combination of excessive dust from bucket elevators and an ignition point that likely began when a number of electric motors covered in sugar dust overheated¹. Other potential ignition sources could have been a spark, friction-induced hot surface, static discharge, or open flame.
¹"Investigation Report: Sugar Dust Explosion and Fire, Imperial Sugar Company." U.S. Chemical Safety and Hazard Investigation Board(2009): 35. Web.