Hank Paul
Market Development Manager for Europe, Middle East & Africa 
BS&B Pressure Safety Management B.V.

The materials we handle in feed mills and silos may appear harmless, but suspended dust clouds and equipment friction can trigger catastrophic explosions in seconds. Safety cannot be left to luck. To eliminate these hidden fire and explosion hazards, high-risk equipment, unseen ignition sources, and the protection systems required when prevention is not enough must be addressed through a comprehensive approach.

Grain silos and feed mills handle large volumes of organic materials that can create a serious industrial hazard caused by combustible dust. Flour, grain, soy meal, starch, feed additives and other fine materials may appear harmless, but when suspended in air, they can burn extremely rapidly and cause explosions. In enclosed equipment such as bucket elevators and conveying systems, heat and friction can ignite a small fire that may turn into a major incident.

Effective safety depends on three principles: prevent combustible dust from accumulating, eliminate ignition sources, and limit the consequences if an incident occurs. 

THE HAZARD

Feed mills generate fine combustible dust during handling, grinding, conveying and drying. If this dust ignites, the results can include injuries, fatalities, equipment damage, production losses and even permanent plant closure.

Recent incidents demonstrate the seriousness of the risk. In February 2026, a Perdue Farms feed mill in Cofield, North Carolina, experienced an explosion that resulted in one fatality and left three people injured. Other examples include a 2023 fishmeal explosion in Norway, a 2023 grain-silo explosion in Türkiye that claimed two lives and injured seven others, and the 2017 Didion Milling corn-dust explosion in the United States, which resulted in five fatalities and 14 injuries.

Grain, corn, wheat middlings, soy meal and many other feed ingredients are combustible. Grinding these materials into fine particles greatly increases their surface area, allowing combustion to travel rapidly through a suspended dust cloud.

A particularly serious danger is a secondary explosion. A small primary explosion can disturb layers of dust that have settled on floors, beams, ledges and ductwork. The released dust can form a much larger cloud and ignite, potentially causing extensive destruction. Even a thin layer of accumulated dust can provide significant fuel.

HIGH-RISK EQUIPMENT

Bucket elevators contain dusty atmospheres and can develop hot spots from belt misalignment, worn bearings or friction between the belt and casing. Foreign objects can also create ignition sources. Because elevators connect different areas of a plant, explosions can spread rapidly throughout the facility. The loss of function of a bucket elevator can disable the operations of an entire facility.

Dust collectors and filters concentrate fine dust and can be ignited by rogue material sparks from rocks and metal staples in the air flow, smouldering material or static electricity. Their connection to extensive ductwork makes them a conduit for explosion propagation.

Hammermills and grinders are major ignition risks. Tramp metal, stones or other foreign objects can create sparks when they enter the grinding chamber. Overloading or blockages can also cause overheating.

Pellet mills, dryers and coolers generate or handle heat. Smouldering product, accumulated fines and restricted airflow can create fires that remain unnoticed and spread downstream.

Conveyors can also become ignition sources. Poorly lubricated or seized bearings may overheat, while dust-covered motors cannot dissipate heat effectively. Belt slippage and misalignment add further friction.

Silos present the additional risk of fires that smoulder inside stored material. Poorly cooled ingredients can self-heat, creating hot spots that may remain hidden for days.

Filling a silo can also create a dust cloud in the headspace. Static electricity or another ignition source can ignite this cloud.

Prevention begins with process control. Temperature monitoring inside stored material and carbon monoxide detection in the headspace can provide early warning. Explosion vents, grounding and bonding, and isolation of elevators and conveyors can reduce the consequences of an incident.

If a silo fire is suspected, personnel should not open hatches to inspect it. Introducing fresh air can intensify combustion, while disturbing the material can create a more dangerous dust cloud. A written emergency plan should address process shutdown of air flow, sealing openings, contacting emergency services and involving specialists where necessary.

AI rendererd Process Flow Diagram

COMMON IGNITION SOURCES 

Common ignition sources include friction and overheated bearings, tramp metal and mechanical sparks, static electricity, electrical faults or unsuitable electrical equipment, welding and other hot work, and self-heating of damp or oily stored ingredients.

Hot work requires particular attention because welding and cutting sparks can ignite dust accumulated inside or around equipment.

PREVENTION

Housekeeping is fundamental. Dust should be regularly removed from floors, ledges, beams and equipment and the cleaning frequency should be based on the rate of dust accumulation. Suitable vacuum cleaning systems for combustible dust should be used; never moving dust using compressed air, which can create airborne dust clouds.

Dust control should begin at the source. Transfer points should be enclosed, equipment sealed and effective aspiration provided to deliver this combustible fuel to a dust collection system and  to prevent dust from escaping into the workplace.

Stray-metal removal is equally important. Magnets and screens should be installed upstream of bucket elevators, mills and grinders, with regular inspections to ensure they continue to function effectively.

Monitoring provides another layer of protection. Temperature sensors, belt-alignment and speed monitors, and motor-current monitoring can identify developing problems. Where appropriate, these systems should be connected to automatic shutdowns to prevent further damage in the facility.

Electrical equipment in classified dust areas must be appropriately rated. Conveyors, ducts and machinery should be bonded and grounded to control static electricity.

Hot-work permits should require the area to be cleaned, combustible materials removed or protected, a fire watch maintained and the area inspected again after work is completed.

PROTECTION WHEN PREVENTION FAILS 

Prevention cannot eliminate every risk, so facilities also require fire protection and explosion prevention.

Explosion venting can provide a safe controlled path for the pressure and flame created by combustion of dust when directed away from people and equipment.

Suppression systems detect an explosion in a very early stage and deploy inert gas and powder to extinguish the combustion event before it becomes an explosion.

Isolation devices, including chemical barriers, rotary valves and fast-acting valves, prevent combustion from propagating through connected ductwork and equipment, reducing the potential for secondary explosions.

Spark detection and extinguishing systems identify glowing particles in ducts and extinguish them before they reach dust collectors or other vulnerable equipment.

The appropriate combination depends on the equipment and process; making a formal explosion risk assessment essential.

STANDARDS, TRAINING AND SAFETY CULTURE

NFPA standards provide an important reference for combustible-dust safety. NFPA 660 covers combustible-dust management and dust hazard analysis with specialized chapters devoted to common processes such as those found in agricultural and food-processing facilities. European operations should also consider the ATEX directives covering equipment and workplaces where explosive hazards may occur.

Technology alone cannot keep a facility safe. Operators and maintenance teams must recognize warning signs such as unusual smells, hot bearings, dust leaks and tripped protection systems. Workers should feel empowered to stop equipment when they identify a serious hazard.

Management-of-change procedures should also evaluate fire and explosion risks whenever equipment or product formulations are changed. Every safety system must be designed for the intended risk; if that risk is changed, revision to the safety system may be required.

THE SAFETY WALKTHROUGH 

Before starting work, confirm that magnets and screens upstream of grinders are clean and working; bearing, belt and motor monitoring systems have been tested and are connected to shutdowns; dust is regularly removed using suitable vacuum systems; and explosion vents, suppression systems and isolation devices remain appropriate for the current dust explosion risk-assessment document. The presence of explosion vents alone, often delivered with OEM equipment, is typically a sign that additional protection measures are required and that the safe vent trajectory of those explosion vents is verified.

FROM RISK TO RESILIENCE 

Fires and explosions in feed mills and silos rarely result from a single failure. They usually occur when several weaknesses align: accumulated combustible dust, an uncontrolled ignition source, and inadequate or poorly maintained protection systems.

A strong safety programme combines good housekeeping, effective dust control, equipment monitoring, ignition prevention, explosion protection systems, employee training and a safety culture that encourages workers to act when they see a hazard. By controlling the fuel, eliminating ignition sources and limiting the consequences when prevention fails, feed mills and silos can significantly reduce the risk of catastrophic fires and explosions.

Safety is not a one time fix!
It is a continuous process of inspection, maintenance, monitoring and disciplined action!