Combustible dust refers to fine particles of solid materials that can catch fire or explode when suspended in air. These particles are typically under 420 microns in diameter, meaning they are small enough to float and ignite easily. The fine texture gives them a larger surface area relative to their volume, allowing for faster dust combustion once an ignition source is introduced.

The materials themselves might not be considered dangerous in bulk form. But, once ground into dust, even substances like grain, wood, metal, or plastic can become highly reactive. In these cases, is dust flammable? Yes, under specific conditions, many types of dust are flammable and pose serious risks. However, dust made from dirt is not flammable.

Dust buildup can affect air quality, trigger respiratory issues, damage equipment, and fuel fires or explosions. Dust that accumulates on surfaces and remains undisturbed can become airborne with the slightest vibration, creating a dangerous cloud of particles ready to ignite.

If your facility processes materials that generate dust, whether from food, metals, pharmaceuticals, or chemicals, you are likely dealing with combustible dust and must implement prevention strategies. Regular inspections, air quality monitoring, and proper ventilation are essential for minimizing the risk.

There are several categories of combustible dust, each associated with specific industries:

• Organic dust: From materials like flour, sugar, grain, wood, and paper
• Metal dust: From aluminum, zinc, magnesium, and other metals
• Chemical dust: Includes sulfur, coal dust, and pharmaceutical ingredients

Other examples include rubber, plastic, dyes, and textile fibers. These particles can vary in moisture, size, and density, which are all factors that influence how likely they are to ignite.

The OSHA combustible dust standard outlines mandatory safety protocols for facilities handling materials that can generate combustible dust. These standards emphasize:

• Proper ventilation systems
• Housekeeping programs
• Dust collection equipment
• Ignition source control
• Employee training

OSHA works in coordination with the National Fire Protection Association (NFPA) to align safety practices. Specifically, NFPA 652 and the more recently consolidated NFPA 660 provide detailed guidelines for assessing and controlling dust hazards.

Compliance with these standards is not just a regulatory obligation; it’s a core component of operational safety. Failing to follow these protocols can result in fines, legal consequences, and, more importantly, preventable accidents.

Preventing a combustible dust explosion starts with a proactive and disciplined approach to safety. Dust hazards can be controlled, but only when facilities implement a comprehensive management plan that includes regulatory compliance, employee training, proper equipment, and regular inspections. Managing combustible dust safety requires a layered system of defense, starting from workplace design to the behaviors of every individual on-site.

A critical part of managing combustible dust risk is understanding where dust accumulates and what might cause it to ignite. Common ignition sources include electrical equipment, static electricity, mechanical friction, and hot surfaces. Even a small spark can lead to a catastrophic dust explosion if conditions are right.

Facilities should conduct a formal Dust Hazard Analysis (DHA) to evaluate where and how flammable dust may pose a risk. A DHA should be performed for every new process and reviewed at least every five years, as required by combustible dust standards. This assessment should include each compartment of the facility and consider both routine and non-routine operations. When performed correctly, a DHA identifies all potential fuel sources (dust) and ignition points, giving safety teams a clear blueprint for mitigation.

Dust hazard assessments must be supported by regular cleaning. Facilities should use certified combustible dust vacuum cleaners, such as Nilfisk’s VHS110, to safely remove settled dust without dispersing particles into the air. These industrial vacuums are specifically engineered to meet combustible dust standard requirements and help maintain clean, compliant workspaces. Ventilation and filtration systems should also be inspected regularly to ensure proper operation and to prevent unexpected buildup.

Everyone on the floor plays a role in combustible dust safety. Employee training is essential not only for compliance but for creating a culture where safety is second nature.

Workers should be trained to:

• Recognize different types of combustible dust
• Identify signs of dangerous buildup in both visible and hidden areas
• Understand how to avoid creating a dust cloud, which can quickly lead to a dust combustion incident
• Know how to properly use industrial vacuum systems and cleaning tools
• Report issues to the appropriate supervisor or safety team member
• Follow established emergency response plans in case of fire, explosion, or ventilation failure

Training must be ongoing, with regular refreshers and scenario-based exercises to reinforce best practices. This is especially important in facilities where materials change frequently or where processes involve high-speed equipment that increases the chance of generating fine dust.

While OSHA combustible dust standards and NFPA combustible dust safety guidelines have been outlined earlier, it’s important to reinforce their role in any dust management plan. These standards provide the framework for keeping facilities compliant and reducing the risk of fire or dust explosion.

At a minimum, businesses should ensure they have completed a Dust Hazard Analysis, established a written housekeeping program, and are using properly certified equipment. Adhering to both OSHA and NFPA regulations helps create a safer environment and supports long-term combustible dust compliance.

Download our dust safety e-book to learn how to comply with combustible dust regulations.

Effective cleaning is a critical part of combustible dust safety. According to NFPA 660, facilities must have a documented housekeeping plan that outlines how often cleaning should take place and how much dust can safely accumulate before removal is required.

The cleaning method you choose should minimize the risk of stirring dust into the air, where it can become explosive. Vacuuming is the preferred method because it captures dust without creating a dust combustion hazard. Sweeping and water washdowns are only recommended when vacuuming isn’t practical.

When using vacuums to collect combustible or flammable dust, NFPA 660 sets specific requirements depending on the environment. In hazardous or classified areas, vacuums must be certified for that location. In non-classified spaces, they still need to meet strict safety design standards.

Here’s what to look for in an industrial combustible dust vacuum:

• Made with conductive materials to prevent static buildup
• Hoses and attachments that are static dissipative or conductive
• All components must be properly grounded and bonded
• Motors and fans should be placed on the clean side of the filter system
• No paper filters when vacuuming liquids or damp materials

Using the right vacuum ensures your facility not only meets combustible dust standards but also reduces the risk of a combustible dust explosion caused by improper cleaning methods.

The risks associated with flammable dust are too great to ignore. Compliance with combustible dust standards is more than just meeting regulations; it’s about protecting lives, property, and business continuity.

Nilfisk has been a leader in industrial cleaning for more than a century. Our industrial combustible dust vacuums are trusted across industries for their durability, reliability, and adherence to combustible dust safety requirements.

Contact our team today to request a quote. Let us help you implement a dust control system that meets your needs and exceeds expectations.