Admittedly, this was news to me. It seems unlikely that items like sugar, soap, or flour would be explosive. Sure, I saw Fight Club, where Tyler Durdin uses household chemicals and soap to intentionally blow thing up, but hadn’t considered that the right circumstances, sugar or soap dust will explode.
So I began looking into it more. What I learned is that if dust is suspended in air in the right concentration, under certain conditions, it can become explosive. Dust can burn rapidly when it’s in a finely divided form. Typically, the finer the dust, the more explosive it can be. This even includes materials that do not burn like aluminum or iron. Plus, these explosions can and have caused injuries and even deaths. Entire buildings have been destroyed from sugar explosions!
The U.S. Chemical Safety and Hazard Investigation Board (CSB) identified 281 combustible dust incidents between 1980 and 2005 that led to the deaths of 119 workers, injured 718, and extensively damaged numerous industrial facilities.
In April 2012, a pasta manufacturer in Steeleville, IL had to send to maintenance employees to the hospital following an explosion outside a metal trough. The employees were welding a repair a hole in the side of the metal trough which was leaking granulated sugar within several feet of an operating dust collector. The dust collector exploded due to a spark from the welding.
Three workers were killed in a 2010 titanium dust explosion in West Virginia, and 14 workers were killed in a 2008 sugar dust explosion in Georgia.
These kind of explosions can occur in a wide variety of industries. A wide variety of materials that can be explosible in dust form exist in many industries. Some industry examples include: food (e.g., candy, sugar, spice, starch, flour, feed), grain, tobacco, plastics, wood, paper, pulp, rubber, furniture, textiles, pesticides, pharmaceuticals, dyes, coal, metals (e.g., aluminum, chromium, iron, magnesium, and zinc), and fossil fuel power generation.
Of all dust explosions, grain are often severe. Over the last 35 years, there have been over 500 explosions in grain handling facilities across the United States, which have killed more than 180 people and injured more than 675. Grain dust is the main source of fuel for explosions in grain handling. Grain dust is highly combustible and can burn or explode if enough becomes airborne or accumulates on a surface and finds an ignition source (such as hot bearing, overheated motor, misaligned conveyor belt, welding, cutting, and brazing).
OSHA does have standards for grain elevators. These require that both grain dust and ignition sources must be controlled to prevent explosions. Interestingly though, there is no specific OSHA standard for combustible dust in general.
How have you succeeded in reducing the risk of combustible dust in your industry?