The Hidden Danger in Plain Sight: Understanding ATEX and Combustible Dust Safety

Sugar. Flour. Wood shavings. On their own, none of these look remotely dangerous. But get them airborne in the wrong conditions, and they behave less like harmless powder and more like an explosive, with force to match.

That risk is real, not theoretical. On 17 July 2015, a huge explosion tore through Wood Treatment Ltd’s mill in Bosley, Cheshire, killing four workers, Dorothy Bailey, Derek William Barks, Derek Moore and Jason Shingler and injuring several others. According to BBC News, the exact cause was never confirmed, but the explosion is thought to have involved wood dust, a material most of us would sweep away without a second thought.

Combustible dust explosions remain one of the most underestimated hazards in UK industry. Here’s what makes dust dangerous, why ATEX and DSEAR regulations exist, and how the right dust control strategy keeps your people safe.

What Makes Dust Dangerous?

The science is simple, even if the risk is often overlooked. When fine particles of combustible material — grain, sugar, metal, wood, almost anything that burns — become suspended in air at the right concentration, they form an explosive atmosphere. All it takes then is a spark or a hot surface to set it off. Industry guidance from Sigma-HSE puts the threshold at around 500 microns: below that size, particles have enough surface area relative to their mass to burn very quickly once airborne.

Here’s an easy way to picture it. A log won’t explode. Saw that same log into fine dust, suspend the particles in air, and you’ve built the conditions for one.

Five conditions have to line up for a dust explosion to happen:

• Fuel – combustible dust
• Oxygen – present in ordinary air
• An ignition source – a spark, hot surface, or static discharge
• Dispersion – enough dust suspended in the air
• Confinement – an enclosed or partially enclosed space

Together, these five are widely referred to in industry safety literature as the “Dust Explosion Pentagon.” Take away just one, and the explosion can’t happen. That’s the entire logic behind effective dust control.

Real Incidents, Real Cost

The UK has learned this lesson more than once. In 2003, a dust explosion at the British Sugar refinery in Cantley, Norfolk, caused serious damage, though thankfully no one died. According to Food and Drink Technology, the explosion started when welding repairs on the outside of a bucket elevator ignited accumulated sugar dust, and it then propagated through the plant’s dust extraction system.

In December 2020, a silo holding treated biosolids exploded at a Wessex Water site in Avonmouth, near Bristol, killing four people. As Chemistry World reported at the time, the precise cause was still under investigation, with HSE guidance pointing to either a build-up of methane or, if the material had been sufficiently dried, a dust explosion. Then in February 2021, fifteen fire crews were called to a fire at a British Sugar processing plant in Bury St Edmunds, Suffolk. Reporting by Suffolk News later confirmed British Sugar’s own early findings: the fire was caused by a spark within a build-up of dust particles under a conveyor belt.

The scale of the wider problem is tracked by Dust Safety Science, an industry body that has logged combustible dust incidents since 2016. According to data reported by Feed & Grain, wood and wood products have accounted for between 21% and 28% of recorded combustible dust incidents every year since 2017. Separately, Canadian Biomass Magazine reported that dust collectors — the very equipment designed to protect workers — were involved in 21.8% of all incidents recorded in 2019, more than any other type of equipment.

Understanding ATEX: Your Legal Safety Net

This is where ATEX regulations come in. As HSE explains, the name comes from the French “ATmosphères EXplosibles,” referring to two European Directives that govern explosive atmospheres — including those created by combustible dust.

In the UK, the workplace directive is implemented through the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR). DSEAR places clear legal duties on employers. You must:

• Assess the risks from explosive atmospheres in your workplace
• Eliminate or control those risks through appropriate measures
• Classify areas where explosive atmospheres may occur into hazardous zones
• Ensure equipment used in those zones is properly certified
• Mark hazardous areas with the yellow and black triangular “Ex” warning sign

Equipment is categorised by the level of protection it offers. Under the standard zone-to-category mapping used across the industry (see Kamat’s ATEX guidance), Category 3D equipment is the minimum required for Zone 22 areas, where an explosive dust atmosphere is unlikely during normal operation but could occur briefly. Category 2D is required for Zone 21, where an explosive atmosphere is likely to occur occasionally during normal operation. Getting this classification right isn’t a box-ticking exercise — it’s how you make sure the equipment on your site can’t become the ignition source itself.

Practical Prevention: Building a Safer Workplace

So what does good dust control actually look like in practice? It comes down to five connected habits.

1. Housekeeping is your first line of defence.

Regular, thorough cleaning stops dust accumulating before it becomes a hazard. Pay close attention to the places it’s easy to miss — ceiling voids, ledges, the tops of equipment — where dust settles unnoticed. No dust, no explosion risk. It’s that simple.

2. Effective extraction captures dust at the source.

This needs to happen before it ever becomes airborne. A properly sized extraction system, fitted with the right filtration, does the heavy lifting here. If it’s installed in a hazardous zone, it needs to be ATEX-compliant — no exceptions.

3. Control your ignition sources.

Strict hot work permits, well-maintained equipment, and proper earthing and bonding to dissipate static electricity all reduce the chance of a spark finding fuel. Even something as small as a loose screw striking machinery can be enough to trigger an explosion.

4. Get your risk assessment and zone classification right.

This work should be carried out by competent professionals who understand where explosive atmospheres could realistically form in your facility, so you can target controls where they matter most.

5. Train your people.

Your team should be able to recognise hazardous dust build-up, understand why housekeeping standards exist, and know exactly what to do if something goes wrong. Well-trained workers are often the first line of defence, long before an incident becomes serious.

A Proactive Approach to Safety

Bosley. Norfolk. Avonmouth. Bury St Edmunds. Each is a reminder that combustible dust explosions are a real, ongoing risk in UK industry. But also that they’re preventable. With the right awareness, equipment, and procedures in place. That risk can be managed down to something manageable, not eliminated by luck.

ATEX and DSEAR aren’t bureaucratic hurdles. They’re hard-won lessons from past disasters, turned into a framework that identifies risk and stops it becoming tragedy.

The Dustcontrol Group was founded in Sweden in 1972, and Dustcontrol UK has been established here since 1996. We have nearly 30 years of helping UK companies work through exactly these challenges. Every regulation, every piece of equipment, exists for one simple reason. To get your workers home safely at the end of the day.

Don’t let combustible dust stay a hidden danger in your facility. Contact us to find out more about our dust control solutions today. Because when it comes to explosive hazards, prevention always beats recovery.