DSEAR vs COSHH: What COSHH Does Not Cover

Key Points

Two regulations, two kinds of harm: COSHH covers harm to health from exposure, DSEAR covers fire, explosion and similar energy-releasing events.

DSEAR reaches further than fire: since June 2015 it also covers gases under pressure and substances classified as corrosive to metals.

The same substance can need both: a solvent that harms the lungs and also ignites sits under COSHH and under DSEAR.

It expects its own risk assessment: Regulation 5 requires a suitable and sufficient assessment of the risks from every dangerous substance present.

Your Safety Data Sheets are a legal input: DSEAR requires the assessment to consider supplier safety information, including any relevant Safety Data Sheet.

Recording is a duty at five employees: employers with five or more must record the significant findings, as under COSHH.

COSHH and DSEAR are separate legal duties covering different dangers from the same substances. COSHH protects health from exposure. DSEAR, the Dangerous Substances and Explosive Atmospheres Regulations 2002, protects people from fire, explosion, pressurised gases and substances corrosive to metals. Each requires its own risk assessment, and both draw on the same Safety Data Sheets.

Ask most businesses about chemical safety and they will talk about COSHH. DSEAR comes up far less often, and that is where the exposure tends to sit.

The same drum of solvent can be a health hazard and a fire hazard at once. So how do the two fit together, and what does DSEAR ask of you that COSHH does not?

How DSEAR differs from COSHH

COSHH, the Control of Substances Hazardous to Health Regulations 2002, is about protecting health from exposure. The slow harm of breathing a vapour or absorbing a substance through the skin.

DSEAR is about protecting people from the physical dangers those same substances carry. Fire, explosions, and events that release energy suddenly. One guards the lungs and skin over months and years. The other guards against something that happens in a second.

The two sit side by side in the statute book, made within weeks of each other in 2002, and they are entirely separate duties with separate assessments. A business that has done COSHH well can still have done nothing about DSEAR.

Which substances DSEAR covers

DSEAR covers four categories of dangerous substance. Anything that could cause a fire or an explosion under the conditions of the work, which means flammable liquids and their vapours, flammable gases, oxidising agents and combustible dusts. And since June 2015, two more: gases under pressure, and substances classified as corrosive to metals.

That extension is the part most often missed, because the name of the regulation says nothing about it. HSE guidance on controlling fire and explosion risks confirms the wider scope and the duty to assess those risks and put control and mitigation measures in place.

Combustible dust deserves its own mention. The fine dust from cutting, sanding or handling certain materials can ignite in a cloud, which surprises people who have never thought of wood or flour as a chemical hazard.

If your workplace stores solvents, refuels vehicles, handles gas cylinders, holds pressurised or corrosive products, or generates combustible dust, DSEAR is very likely in scope whether anyone has named it.

The everyday DSEAR substances

DSEAR is not a chemical plant regulation. Petrol and diesel, cleaning solvents, aerosols, LPG, welding gases, ammonia and wood or flour dust are all dangerous substances in the right conditions. The regulation reaches far more ordinary workplaces than its name suggests.

What DSEAR requires you to do

The shape will feel familiar from COSHH, with the focus on physical danger rather than health. The duties run in sequence:

Assess the risks. Regulation 5 requires a suitable and sufficient assessment covering the hazardous properties of each substance, the supplier's safety information, the work processes and quantities involved, and the risk from substances acting in combination.
Eliminate or reduce the risk so far as is reasonably practicable, by substituting something less hazardous, holding less of it, or changing the process.
Control what remains and mitigate the consequences, from managing ignition sources and ventilation through to equipment design and written procedures.
Classify the places where an explosive atmosphere may occur. Regulation 7 requires those areas to be sorted into hazardous and non-hazardous, then the hazardous ones into zones, with equipment and working practices matched to each zone.
Record the significant findings where you employ five or more people and review the assessment when it may no longer be valid or when the work changes significantly.

That last pair will look identical to your COSHH obligations, because it is the same threshold and the same review trigger. The assessment underneath it is a different document answering a different question.

The mistake that costs most

A thorough COSHH Assessment can leave your fire and explosion risk entirely unexamined. COSHH may say nothing about ignition sources, static, or an explosive vapour building in a poorly ventilated store. The same substance can be well controlled for health and still ignite. If you have never done a DSEAR assessment for your flammables, that is a gap to close now.

Why your Safety Data Sheets serve both duties

Here is the part that saves you work, and it is stronger than a practical convenience. Regulation 5 explicitly requires the DSEAR assessment to consider the safety information provided by the supplier, including the information in any relevant Safety Data Sheet. The document you already keep for COSHH is a named statutory input to the other duty.

Look at where the information sits. Section 2 flags health hazards for COSHH and physical hazards such as flammability for DSEAR. Section 9 gives the properties DSEAR turns on, flash point among them. Section 7 covers safe storage and handling that both duties rely on.

A complete substance inventory backed by current sheets is the groundwork for both. Which means the work you already do keeping your COSHH data current and provable is already doing a good share of the DSEAR job.

One inventory, both duties

Here is how the gap shows up in practice.

A busy vehicle workshop has the COSHH side handled. Assessments for the solvents and the brake cleaner, gloves issued, ventilation sorted. Then a DSEAR question arrives. Where do flammable vapours collect. Are ignition sources controlled near the solvent store. Is there a risk of an explosive atmosphere in that back room.

If nobody can answer, the business is compliant on health and exposed on fire, from the very same chemicals.

Now the same workshop with a complete, current substance inventory. The flammables are already listed. Their flash points are already visible. The DSEAR assessment starts from data instead of a blank page, and the questions that felt like an ambush become a morning's work.

That shared foundation is the point. Sevron's Accelerated Compliance approach is built on knowing your substances and keeping that knowledge current, and while DSEAR needs its own fire and explosion assessment, Safety365 holds the substance inventory and the current Safety Data Sheets that both COSHH and DSEAR stand on. Get the data right once and both duties become work you can actually do.

Have you assessed your flammables under DSEAR, or only under COSHH?

Talk to our team about getting your substance data working for both duties.

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Frequently Asked Questions

What does DSEAR stand for?

The Dangerous Substances and Explosive Atmospheres Regulations 2002. It is the UK regulation covering risks to people from fire, explosion, pressurised gases and substances corrosive to metals in the workplace.

What is the difference between COSHH and DSEAR?

COSHH protects health from exposure to hazardous substances. DSEAR protects people from fire, explosions, pressurised gases and substances corrosive to metals. Different dangers, separate assessments.

Does my COSHH Assessment cover DSEAR?

No. COSHH addresses health rather than fire and explosion, so a separate DSEAR assessment is required, though both draw on the same substance data.

Which substances fall under DSEAR?

Flammable liquids and vapours, flammable gases, oxidising agents and combustible dusts, plus gases under pressure and substances classified as corrosive to metals since the 2015 extension.

Does DSEAR apply to my workplace?

If you store or use flammable liquids, gases, aerosols or fuels, hold pressurised or corrosive products, or generate combustible dust, it very likely does. DSEAR reaches far more than chemical plants.

Do I have to write down a DSEAR assessment?

Employers with five or more employees must record significant findings, including the measures taken and the details of any areas zoned as hazardous. The same threshold applies under COSHH.

What is hazardous area classification?

The process required by Regulation 7 of sorting workplace areas into hazardous and non-hazardous, then classifying hazardous ones into zones. Equipment, protective systems and working practices then have to match the zone.

The solvent that harms the lungs is the same solvent that catches fire. Two duties, one inventory. See how Safety365 keeps the data both rely on.