Persons who work inside industrial facilities have to be well aware of the variety of potential hazards they may encounter while on the job. There can be a number of threats present at any time, depending on the type of building and the kinds of industrial processes found inside it—radiation, noxious gases, poisonous chemicals, and much more.
There is one particular threat, however, that receives too little attention—and ignorance of this phenomenon can have deadly consequences. We’re referring to combustible dust. Not only can combustible dust trigger massive explosions, but it is often misjudged as an industrial hazard because this particulate matter often comes from seemingly benign sources. As we will see, though, this is not a topic that should be ignored.
Introduction to Combustible Dust
Fine airborne particles that can catch fire or explode—that is combustible dust. The particulate matter may be organic materials, metallic materials, or inorganic non-metallic materials.
It’s worth keeping in mind that some types of combustible dust are composed of materials that are, under most circumstances, inert. They can catch on fire only if the particles reach a certain level of concentration. These kinds of dust can be especially hazardous precisely for that reason, as persons in the area may have good cause to believe that no danger is present.
Combustible dust can settle on a variety of surfaces—equipment, desks, floors, and more—and become airborne due to human or mechanical activity in the area. However, it can’t catch on fire without a source of ignition, such as heat or open flame. Additionally, combustion cannot occur unless oxygen is present in the air.
Types of Combustible Dust
This kind of hazardous particulate matter is more common than you probably think—it can be found across a wide range of industries, including the rubber, paper, plastics, pharmaceutical, textile, and tobacco sectors.
Any of the following materials can be combustible when in dust form:
| Cotton | Starch | Carrots | Garlic | Rice flour |
| Parsley | Milk | Sugar | Whey | Soy flour |
| Charcoal | Soot | Corn | Cork | Wheat flour |
| Ascorbic acid | Sulfur | Lactose | Zinc | Aluminum |
| Bronze | Epoxy resin | Polyacrylamide | Polypropylene | Vinyl acetate |
Bear in mind that this is only a partial list of combustible dust matter.
Places Where a Combustible Dust Accident Can Occur
If a given workplace environment generates dust, it is very likely to be vulnerable to a combustible dust explosion. Remember that dust isn’t merely what collects on surfaces that go extended periods without seeing use. There are, in fact, many ways to generate this type of particulate matter. Dust can be created by the cutting, crushing, polishing, grinding, shaping, recycling, or processing of certain materials.
Confined spaces are particularly susceptible to incidents with combustible dust, as explosions cannot occur unless there is an adequate concentration of “fuel” in the air.
How Explosions Happen
Airborne dust can explode in the presence of a source of ignition and a sufficient amount of oxygen. Often, explosions occur when settled dust is dislodged by movement (e.g., machinery is turned on after a long hiatus) and comes into contact with heat or flame.
The destructive power of a combustible dust explosion can be attributed to the fact that, in many cases, it is really two explosions that occur in quick succession. The airborne dust that is initially ignited tends to be only a small portion of the total particulate matter in the area.
When the dust cloud explodes, it dislodges the rest of the particulate material—which promptly comes into contact with the ignition source, triggering a second explosion that often surpasses the force of the first. It’s even possible for the secondary explosion to set off additional ones.
Several Case Histories
Make no mistake: combustible dust explosions can cause massive damage. This should be made clear by examining a few well-known incidents:
- In 1999, a Massachusetts foundry was the site of an organic dust explosion that killed 3 people. The explosion was eventually traced to a fire inside a shell molding machine. The conflagration rapidly grew when the flames encountered substantial amounts of resin dust deposits inside the ventilation ducts. The force of the secondary explosion knocked down walls and lifted the roof.1
- In 2003, 6 people died and 38 others were injured at a pharmaceutical plant in North Carolina due to polyethylene dust that accumulated above the facility’s suspended ceilings. The explosion was large enough to damage several nearby buildings. The ignition source was never found.1
- In 2008, an explosion at the Imperial Sugar Company facility in Port Wentworth, GA killed 14 workers and injured dozens. Investigators found that sugar dust buildup and poor housekeeping created dangerous conditions, allowing ignition to trigger a powerful explosion and widespread fires.2
Industrial Safety Precautions
Luckily, these types of incidents are far from inevitable. Here are a handful of tips for preventing combustible dust accidents:
- Clear out accumulations of dust. Some simple janitorial service can quite literally be a lifesaver. Be sure to check areas where dust buildup can’t be easily seen—it may be out of sight, but it can still be ignited if a fire breaks out.
- It’s best to use a vacuum to remove dust, as brooms and hoses tend to leave significant amounts of particulate matter behind.
- Remove ignition sources when possible. Remember that these explosions are commonly set off by heat and/or open flame.
- Ensure proper ventilation. This can prevent hazardous dust clouds from forming.
- Consider installing dust collection systems. If regular cleaning is not enough to keep up with significant amounts of dust, specialized industrial safety equipment like a dust collector can gather it automatically for later disposal.
OSHA Compliance and Inspection Readiness
Maintaining compliance with OSHA combustible dust safety standards helps reduce risk and supports inspection readiness. Employers should conduct a dust hazard analysis to identify materials that can ignite under specific conditions, including particle size and ignition sources.
Keep detailed records of all cleaning schedules, equipment maintenance, employee training, and other related tasks. These records show a consistent safety process, which OSHA will want to see on inspection.
Housekeeping Best Practices for Dust Control
Effective housekeeping helps prevent combustible dust from reaching hazardous levels. Focus on consistent cleaning and proper methods across all areas.
- Cleaning scope: Address visible dust and hidden areas like overhead beams and equipment surfaces.
- Approved methods: Use industrial vacuum systems designed for combustible dust instead of dry sweeping.
- Air control: Avoid compressed air unless proper containment systems are in place.
- Cleaning schedule: Set frequency based on dust levels and material types, with high-production areas cleaned daily.
- Staff responsibility: Assign trained employees and confirm tasks are completed on time.
- Ongoing checks: Perform regular inspections to catch buildup early and maintain overall workplace safety.
Consistent execution of these practices helps reduce risk and supports a safer work environment.
The Role of Flame-Resistant Apparel
As we have seen, igniting combustible dust can cause a massive, out-of-control blaze. In a lot of cases, death and serious injury aren’t caused by the primary and secondary explosions but rather by the ensuing fire. Many people caught in these blazes have sustained severe harm due to one simple fact: they were not wearing flame-resistant clothing.
So what are the properties of this clothing that make it flame-resistant? Properly designed flame-resistant apparel will not melt or split open when exposed to flame, which protects the skin of the wearer. It also will not permit flame to spread over the surface of the material.
Furthermore, this type of clothing insulates the user from the effects of intense heat. These qualities add up to a substantial degree of protection from fire-related injury—the wearer is not invulnerable to harm, but is much more likely to walk away without suffering lasting effects. Accidents happen, but protective clothing can prevent them from causing disaster.
Professional uniform service from Prudential Overall Supply can help protect your employees from harm due to combustible dust hazards. Contact our uniform supply company today to discuss flame-resistant uniform rental.
Sources
- OSHA. Combustible Dust in Industry: Preventing and Mitigating the Effects of Fire and Explosions.
- U.S. Chemical Safety Board. Imperial Sugar Company Dust Explosion and Fire.