Month: October 2026

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When Does DSEAR Apply?

Short answer: DSEAR applies whenever your work involves a substance that could cause a fire, explosion or similar energetic event. The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) cover far more than heavy industry. Petrol, solvents, LPG, wood dust, flour and even the hydrogen given off by charging forklift batteries can bring a workplace within scope.

This guide explains when DSEAR applies, which activities are excluded and what employers need to do.

What is DSEAR?

DSEAR is the main piece of Great Britain’s health and safety law for protecting people from the fire and explosion risks of dangerous substances at work. It requires employers to assess those risks and then eliminate or reduce them, so far as is reasonably practicable. The regulations are enforced by the Health and Safety Executive (HSE) and, for some premises, local authorities.

What is a “dangerous substance” under DSEAR?

A substance counts as dangerous under DSEAR if it could cause harm through fire, explosion or a similar energetic reaction. This includes:

  • Flammable liquids, such as petrol, solvents, thinners, alcohols and some paints, varnishes and adhesives
  • Flammable gases, such as LPG, propane, acetylene, hydrogen and natural gas
  • Aerosols containing flammable propellants
  • Flammable solids, such as certain metal powders
  • Oxidising substances and organic peroxides, which can feed or intensify a fire
  • Self-reactive, self-heating and pyrophoric substances, which can ignite without an obvious ignition source
  • Substances that give off flammable gas on contact with water
  • Combustible dusts, such as flour, sugar, grain, wood, paper, plastics and some metal dusts, which can form explosive clouds when dispersed in air

Look at hazard pictograms and the supplier’s safety data sheets, these are a good first indicator of whether a substance is covered.

DSEAR

Does DSEAR apply to you?

What is an explosive atmosphere?

DSEAR is particularly concerned with explosive atmospheres. These are mixtures of air and flammable gases, vapours, mists or dusts in which, once ignited, burning spreads through the whole mixture. A small leak in a poorly ventilated room, a cloud of dust in a hopper or vapour from a spray booth can each create one. If there is also an ignition source (a spark, static electricity, a hot surface or an electrical fault), the result can be devastating.

When does DSEAR apply to my business?

DSEAR applies when dangerous substances are present at work, whether you:

  • Use them in a process, such as spraying, mixing, cleaning or welding
  • Store them, for example solvents, gas cylinders or fuel
  • Produce or handle them, intentionally or as a by-product (such as dust from sanding or cutting)
  • Transport them within or around your premises

It applies regardless of business size or sector. Typical examples include:

  • Vehicle repair, spraying and refinishing
  • Woodworking, joinery and furniture manufacture
  • Food and drink production, milling and bakeries
  • Warehousing, including battery charging areas
  • Engineering, welding and fabrication
  • Waste and recycling, where dust, gases and fire risks are common
  • Farms, including grain stores and fuel storage
  • Laboratories, schools and universities
  • Petrol stations and fuel depots

DSEAR protects employees, contractors, visitors and members of the public who could be affected by your work, and self-employed people have duties too. Small quantities can still bring DSEAR into play, although the controls needed should be proportionate to the risk.

When does DSEAR not apply?

DSEAR does not apply to some activities, which are covered by other specific legislation, including:

  • Areas used directly for the medical treatment of patients
  • Appliances burning gaseous fuel that are covered by gas appliance rules
  • The manufacture, handling, use, storage and transport of explosives and chemically unstable substances, which fall under explosives legislation
  • Mineral extraction industries, which have their own regulations
  • Certain forms of transport, such as use of vehicles on public roads, which have separate rules

If you are unsure whether an exclusion applies to your activity, take advice before relying on it – in some cases only parts of DSEAR are disapplied.

DSEAR or COSHH: what’s the difference?

The two sets of regulations are often confused, but they address different harms. COSHH deals with hazardous substances that damage health, such as through inhalation or skin contact. DSEAR deals with substances that can cause fire, explosion and similar events. Many substances fall under both. Solvents, for example, can harm health through exposure and also burn or explode, so you may need to assess the risks under each.

What do I need to do to comply with DSEAR?

DSEAR compliance usually follows these steps:

  1. Carry out a risk assessment. Identify the dangerous substances, how they might ignite or explode and who could be harmed. Consider the quantities, the processes, the possible ignition sources and what could go wrong.
  2. Eliminate or reduce the risk. Substitute with a less hazardous substance where you can, reduce quantities, improve ventilation and control leaks and spills.
  3. Control ignition sources. Use suitable equipment in hazardous areas, manage static, control hot work and keep unsuitable equipment out.
  4. Classify hazardous areas into zones. Where explosive atmospheres may occur, areas are classed by how often and for how long they are likely to be present (zones 0, 1 and 2 for gases and vapours; zones 20, 21 and 22 for dusts). This determines the equipment that can be used there.
  5. Mark hazardous areas where necessary. Display the explosive atmosphere warning sign at entry points.
  6. Mitigate the effects. Use measures such as explosion relief, suppression, isolation and separation, so that harm is limited if an incident occurs.
  7. Prepare for emergencies. Provide procedures, alarms, escape routes and equipment, and practise them.
  8. Inform, instruct and train. Everyone who works with or near dangerous substances must understand the risks and controls.
  9. Review regularly. Revisit your assessment when substances, processes, equipment or layouts change.

What happens if I don’t comply?

Fires and explosions involving dangerous substances can cause fatalities, life-changing injuries and major damage to property and business continuity. HSE can issue improvement and prohibition notices and prosecute, and serious breaches can bring unlimited fines or even imprisonment. Insurers may also challenge claims where a business has not assessed or controlled its risks.

Does DSEAR apply in Northern Ireland and the Republic of Ireland?

DSEAR applies in Great Britain. Northern Ireland has an equivalent set of regulations, the Dangerous Substances and Explosive Atmospheres Regulations (Northern Ireland) 2003, and the Republic of Ireland regulates explosive atmospheres and chemical agents under its own health and safety legislation. The principles are broadly the same, but the details differ, so check the rules that apply where you operate.

Not sure whether DSEAR applies to you?

If your business stores, uses or produces flammable liquids, gases, aerosols or dusts, assume DSEAR is relevant and start by listing the substances you have and where they are. The HSE provides additional guidance for businesses.

This article is general guidance and not legal advice. Requirements depend on your specific work activities and location.

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Does COSHH Apply to My Business?

Short answer: almost certainly, yes. If anyone at your workplace uses, makes, handles or is exposed to substances that could harm their health, the Control of Substances Hazardous to Health Regulations 2002 (COSHH) apply to you. That covers far more businesses than most owners expect, from building sites and factories to salons, schools, care homes and offices.

This guide explains what COSHH covers, who must comply, what is excluded and what you need to do.

What is COSHH?

COSHH is the main piece of Great Britain’s health and safety law governing hazardous substances at work. It requires employers to prevent or adequately control exposure to substances that can cause ill health, whether through breathing them in, skin contact, swallowing or contact with the eyes.

The regulations are enforced by the Health and Safety Executive (HSE) and, for some sectors, local authorities.

Which substances does COSHH cover?

COSHH applies to a wide range of substances hazardous to health, including:

  • Chemicals and products containing them, such as cleaning products, paints, solvents, adhesives, de-greasers and disinfectants
  • Fumes, such as welding or soldering fumes
  • Dusts, such as wood dust, flour dust, silica dust from cutting stone or concrete, and cement
  • Vapours, gases and mists, such as spray mists and exhaust fumes
  • Biological agents, such as bacteria, viruses and fungi, including Legionella in water systems
  • Germs that cause diseases, such as leptospirosis (Weil’s disease) or hepatitis, where work brings people into contact with them
  • Nanotechnology materials, where hazardous
  • Asphyxiating gases, which displace oxygen

Many everyday products carry hazard warning pictograms on the label. These are a good first clue that COSHH is relevant. The supplier’s safety data sheet gives the detail you need for your assessment.

Who does COSHH apply to?

COSHH places duties on employers, but it also protects others affected by your work. You must consider:

  • Your employees and agency or temporary workers
  • Contractors working on your premises
  • Visitors, customers and members of the public who could be exposed
  • Self-employed people, who have duties for their own protection and that of others

Business size doesn’t matter. A sole trader with one employee has the same duties as a large organisation, although the paperwork and controls should be proportionate to the risk.

Does COSHH apply to offices and low-risk workplaces?

Yes, although the risks are usually lower. Offices use cleaning products, toner and printer consumables, and some have air conditioning or water systems that need managing for Legionella. You still need to consider whether any substances could cause harm. In many cases a short, sensible assessment will show that risks are low and existing controls are enough.

What does COSHH not cover?

Some hazards have their own specific regulations, so COSHH does not apply to them:

  • Asbestos, covered by the Control of Asbestos Regulations 2012
  • Lead, covered by the Control of Lead at Work Regulations 2002
  • Radioactive substances and ionising radiation, covered by the Ionising Radiations Regulations 2017
  • Substances hazardous only because they are explosive, flammable, or are at extreme temperature or pressure, which are covered by other legislation such as the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR)

Even where COSHH doesn’t apply, you will normally still have duties under these other regulations and under the Health and Safety at Work etc. Act 1974.

COSHH bucket

Do you know what chemicals are used in your business?

What do I need to do to comply with COSHH?

In practice, COSHH compliance comes down to these steps:

  1. Assess the risks. Identify which hazardous substances are present, who could be exposed, how and how much. Record your significant findings if you employ five or more people.
  2. Prevent or control exposure. Where you can, eliminate the substance or substitute something safer. Otherwise use engineering controls such as enclosure or local exhaust ventilation, safe working systems, and personal protective equipment (PPE) only as the last line of defence.
  3. Make sure controls are used and maintained. Local exhaust ventilation must be thoroughly examined and tested at least every 14 months, and records kept.
  4. Monitor exposure where needed. Compare exposure against the workplace exposure limits in HSE’s EH40 guidance.
  5. Provide health surveillance where required. This applies where there is a risk of identifiable ill health, such as dermatitis or occupational asthma.
  6. Inform, instruct and train your people. Workers need to understand the risks, the controls and what to do if something goes wrong.
  7. Plan for emergencies. Have procedures for spills, accidents and incidents involving hazardous substances.
  8. Review regularly. Revisit your assessment whenever processes, substances or work methods change.

What happens if I don’t comply?

Poor COSHH compliance can lead to serious occupational illness, including occupational asthma, dermatitis, cancers and lung disease, often with effects that appear years later. The HSE can issue improvement or prohibition notices and prosecute, with unlimited fines for serious breaches. Beyond enforcement, you face the cost of civil claims, sickness absence and reputational damage.

Does COSHH apply in Northern Ireland and the Republic of Ireland?

COSHH itself applies in Great Britain. Northern Ireland has its own equivalent, the Control of Substances Hazardous to Health Regulations (Northern Ireland) 2003, and the Republic of Ireland regulates chemical and biological agents under separate legislation. The core principle is the same: assess, control and review. If you operate across more than one jurisdiction, check the requirements for each.

Not sure where you stand?

If your business uses any chemicals, dusts, fumes or biological agents, assume COSHH applies and start by listing the substances you use. If you’re unsure whether your assessments are adequate, our health and safety consultants can help you review your hazardous substances, carry out COSHH assessments and put practical controls in place.

This article is general guidance and not legal advice. Requirements depend on your specific work activities and location.