Flour Dust LEV Requirements for UK Bakeries and Food Manufacturers

Flour dust causes occupational asthma. It is one of the most commonly reported causes of work-related respiratory disease in the UK. Bakery workers, millers, and food production staff who inhale flour dust regularly face significantly higher rates of asthma and rhinitis than the general working population.

Flour dust is classified as a respiratory sensitiser. Once a worker becomes sensitised, even very low exposures can trigger asthma attacks. There is no cure. Sensitisation is permanent. The only effective response is prevention — keeping exposure low enough that sensitisation doesn't develop in the first place.

For most flour-handling operations, that means local exhaust ventilation.

Why Flour Dust Is a Serious Workplace Hazard

Flour dust is fine, light, and disperses readily into the air. Pouring, mixing, sieving, and weighing all generate airborne dust. In a busy bakery or food production line, background flour dust levels can build up quickly without effective extraction.

The health effects are well documented:

• Occupational asthma. Flour is a known respiratory sensitiser under COSHH. Prolonged exposure can cause the immune system to react to flour proteins, leading to asthma that persists even after exposure stops.
• Rhinitis. Inflammation of the nasal passages — chronic sneezing, congestion, and runny nose. Often a precursor to asthma.
• Dermatitis. Flour can cause skin irritation and allergic contact dermatitis, particularly on the hands and forearms.

These conditions develop over time. A worker may handle flour for years before symptoms appear. By the time they do, the damage is done. This latency period is precisely why the regulations focus on prevention through exposure control, not on reacting to symptoms.

Workplace Exposure Limits for Flour Dust

The workplace exposure limit for flour dust is set in EH40:

• Inhalable dust: 10 mg/m³ (8-hour time-weighted average)
• Respirable dust: 4 mg/m³ (8-hour time-weighted average)

These are the general dust limits. They apply to flour dust because flour does not have a substance-specific WEL. However, because flour is a respiratory sensitiser, COSHH Regulation 7 requires exposure to be reduced as far as is reasonably practicable — not merely kept below the WEL. For sensitisers, there is no truly safe level of exposure. The lower you can get it, the lower the risk of workers developing permanent respiratory disease.

In practice, this means any flour-handling operation that generates visible airborne dust almost certainly requires LEV, even if air monitoring shows you're below the WEL.

Where LEV Is Needed in Bakeries and Food Manufacturing

Not every task in a bakery needs extraction. But more tasks need it than many businesses realise. The key operations where flour dust becomes airborne include:

Bag tipping and decanting. Opening and tipping bags of flour generates a concentrated dust cloud at the point of pouring. This is often the highest-exposure task in a bakery. LEV — typically a slot hood or enclosure at the tipping point — captures the dust before it reaches the worker's breathing zone.

Weighing and measuring. Scooping flour from bins and weighing it produces dust, especially with fine or powdered ingredients. An extraction point at or near the weighing station controls exposure during this routine task.

Sieving. Running flour through a sieve agitates it and releases fine particles into the air. Enclosed sieving with extraction is the most effective approach.

Mixing. Adding flour to a mixer — particularly a planetary mixer or spiral mixer running at speed — throws flour dust into the air. LEV at the mixer, or an enclosed mixing process, reduces exposure during the addition stage.

Dough dividing and moulding. These processes use dusting flour to prevent sticking. Every application of dusting flour creates airborne particles. Extraction at the dusting point or use of alternative release agents reduces exposure.

Packaging. Filling bags, pouches, or containers with flour or flour-based products generates dust at the filling point. Enclosed filling with extraction is standard in larger operations.

Cleaning. Sweeping up spilled flour is one of the worst exposure scenarios. A dry brush turns settled flour into a dense airborne cloud. Vacuum cleaning with a HEPA-filtered industrial vacuum, or wet cleaning methods, should replace dry sweeping entirely.

Types of LEV Systems for Flour Dust

The type of LEV depends on the operation and the layout of the workplace.

Enclosing hoods and booths. These surround the dust source — a bag-tipping station inside a partial enclosure with extraction, for example. Enclosing hoods are the most effective type of LEV because they contain the dust before it can disperse. Where the process allows enclosure, this should be the first choice.

Captor hoods. Where enclosure isn't practicable, a captor hood positioned close to the dust source pulls contaminated air away from the worker. Slot hoods along the edge of a work surface, or circular hoods above a mixing point, are common designs. The critical factor is proximity — a captor hood loses effectiveness rapidly as the distance from the source increases.

Downdraft benches. For weighing and measuring operations, a downdraft bench draws air downward through the work surface and away from the breathing zone. This is particularly effective for tasks done on a bench top.

On-tool extraction. For vacuum cleaning of surfaces, an industrial vacuum with HEPA filtration captures flour dust at the nozzle point. This replaces sweeping and keeps settled dust from becoming airborne again.

Specific Challenges With Flour Dust Control

Flour dust presents some challenges that other dusts don't.

Fine particle size. Flour dust is very fine and stays airborne for extended periods. Once dispersed, it takes a long time to settle. This means extraction needs to capture it quickly, before it spreads beyond the reach of the LEV hood.

Food hygiene requirements. Bakeries and food production facilities must comply with food safety regulations as well as COSHH. LEV systems in food environments need to be cleanable, free from harbourage points for pests, and constructed from food-safe materials. Ductwork must not create hygiene risks — no dead legs where product can accumulate, no uncleanable joints.

Humidity and temperature. Bakery environments can be warm and humid. Flour dust in humid air can cake onto duct surfaces and filter media, reducing system performance. LEV systems in bakeries need regular maintenance to prevent buildup in ductwork.

Explosion risk. Flour dust is explosible. At sufficient concentrations in an enclosed space, it can ignite. LEV systems handling flour dust must be designed with explosion protection in mind — explosion relief venting, spark detection, and appropriate earthing. This is particularly relevant for larger installations with dust collectors.

HSE Enforcement in Bakeries

The HSE has historically targeted bakeries and food manufacturing in its dust enforcement campaigns, and the food sector has featured in the HSE's Dust Kills inspection programmes. Occupational lung disease is an HSE strategic priority, and flour dust is one of the named hazards.

During an inspection, the HSE will check:

• Whether a suitable risk assessment identifies flour dust exposure and the controls needed
• Whether LEV is installed at dust-generating operations
• Whether LEV systems have a current TExT report within the 14-month deadline
• Whether records are available showing maintenance and user checks
• Whether workers are trained on flour dust risks and the correct use of LEV
• Whether dry sweeping has been eliminated and replaced with vacuum or wet cleaning

Practical Compliance Steps

1. Map your flour dust exposure points. Walk through every process and identify where flour becomes airborne. Include routine activities and occasional tasks like cleaning.

2. Assess your current controls. For each exposure point, check whether LEV is in place, whether it's adequate, and whether it's being used. Use the LEV compliance checklist generator to build a structured assessment.

3. Check your TExT status. Every LEV system in your bakery must have a current TExT report. Use the LEV testing due date calculator to confirm you're within the 14-month window for each system.

4. Eliminate dry sweeping. If your bakery still uses brooms to clean up flour spillages, stop. Replace with HEPA-filtered vacuum cleaning or wet methods. This single change can significantly reduce background dust levels.

5. Review your cleaning regime. Settled flour dust on surfaces, ledges, and equipment becomes airborne dust when disturbed. Regular, thorough cleaning with appropriate methods keeps background levels down.

6. Train your staff. Every person who handles flour should understand why extraction is there, how to use it, and how to spot when it isn't working. Training should cover the health risks and the importance of reporting problems.

7. Keep records. TExT reports, user check logs, maintenance records — all must be kept and accessible. The record-keeping requirements checker can help you confirm you're meeting the requirements.

LEVproof is being built to help UK food businesses manage LEV compliance — TExT tracking, automated reminders, and digital record-keeping. Join the waitlist for early access.

Sources

• Control of Substances Hazardous to Health Regulations 2002 (COSHH) — legislation.gov.uk
• HSG258: Controlling airborne contaminants at work — HSE
• LEV guidance for employers — HSE
• COSHH main page — HSE
• Work-related lung disease — HSE

This guide summarises published HSE and government guidance. It does not constitute legal advice. Consult a qualified professional for advice specific to your situation.