DSEAR Risk Assessments

Working with flammable, explosive, or otherwise dangerous substances presents a significant risk if those hazards are not properly controlled. Simply being aware that a substance is hazardous is not enough — without suitable precautions, a single ignition source can result in fire, explosion, serious injury, or structural damage.

The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) place clear legal duties on employers and those in control of premises to assess and control these risks.

A DSEAR risk assessment is the primary way of identifying where dangerous substances are present, how explosive atmospheres may arise, and what measures are required to prevent or mitigate incidents.

At Fire Risk Assessment Network, we support organisations across a wide range of sectors by carrying out suitable and sufficient DSEAR risk assessments that are practical, proportionate, and aligned with current UK health and safety legislation.

What Does DSEAR Stand For?

DSEAR stands for the Dangerous Substances and Explosive Atmospheres Regulations 2002.

The regulations are designed to protect people from risks arising from:

• Fires
• Explosions
• Substances corrosive to metal that could compromise safety

DSEAR applies to almost all workplaces, not just high-risk industrial environments. Dangerous substances can be found in offices, retail premises, workshops, warehouses, and commercial buildings, often as part of everyday activities.

What Are the DSEAR Regulations?

Under DSEAR, employers and those with control of premises must eliminate or reduce risks from dangerous substances so far as is reasonably practicable.

According to official HSE DSEAR guidance, employers must find out what dangerous substances are in their workplace and take action to either eliminate or control associated fire and explosion risks.

This includes duties to:

• Identify dangerous substances present or likely to be present
• Assess the risks of fire, explosion, and corrosion of metal
• Implement appropriate control and mitigation measures
• Reduce the effects of any incidents through emergency planning
• Classify hazardous areas where explosive atmospheres may occur
• Select suitable equipment and protective systems
• Provide information, instruction, and training to employees

These duties sit alongside broader health and safety requirements and must be reviewed whenever processes, substances, or layouts change.

What Is a DSEAR Risk Assessment?

A DSEAR risk assessment is a specific assessment that focuses on the risks posed by dangerous substances and explosive atmospheres.

It should demonstrate that:

• Dangerous substances have been identified
• Fire and explosion risks have been evaluated
• Control measures are suitable and effective
• Equipment is appropriate for hazardous zones
• Risks remain controlled during normal and foreseeable abnormal conditions, including maintenance and shutdowns

Control measures and risk assessment approaches should be consistent with the DSEAR Approved Code of Practice (ACOP) and guidance, which explain how to comply with regulatory duties.

A DSEAR risk assessment may form part of a wider health and safety risk assessment, provided it adequately addresses DSEAR requirements.

Why Do You Need a DSEAR Risk Assessment?

Fires and explosions can cause severe harm through:

• Thermal radiation
• Overpressure effects
• Oxygen depletion
• Structural failure caused by corrosion of metal

DSEAR requires employers to understand how dangerous substances could cause harm, not just that they are present.

A suitable and sufficient DSEAR risk assessment helps to:

• Prevent fires and explosions before they occur
• Protect employees, contractors, and the public
• Demonstrate legal compliance
• Support safe equipment selection and zoning
• Reduce enforcement and insurance risk

What Is Classified as a Dangerous Substance?

A dangerous substance is any substance present or used at work that could cause harm as a result of fire, explosion, or corrosion of metal.

Common examples include:

• Liquids – paints, solvents, fuels, adhesives, cleaning chemicals
• Gases – LPG, methane, acetylene, hydrogen
• Solids – combustible packaging materials, textiles
• Dusts – flour, sugar, wood dust, metal powders, animal feed
• Corrosive substances – those capable of damaging metal structures or containers

Many workplaces contain dangerous substances even if they are not the core activity of the business, making DSEAR relevant across a wide range of sectors.

What Is a DSEAR Zone?

A DSEAR zone is a hazardous area where an explosive atmosphere may occur in sufficient quantities to require special precautions.

Gas, Vapour and Mist Zones

• Zone 0 – An explosive atmosphere is present continuously or for long periods
• Zone 1 – An explosive atmosphere is likely to occur occasionally during normal operation
• Zone 2 – An explosive atmosphere is unlikely during normal operation, and if it occurs, will be brief

Dust Zones

• Zone 20 – A cloud of combustible dust is present continuously or frequently
• Zone 21 – A cloud of combustible dust is likely to occur occasionally
• Zone 22 – A cloud of combustible dust is unlikely and will be short-lived

Correct zoning is essential for selecting appropriate equipment and ensuring continued safety.

Further explanation of how DSEAR applies across different workplace scenarios can be found in DSEAR regulations in detail.

Our Experience With DSEAR Risk Assessments

DSEAR risk assessments must be carried out by a competent person with sufficient knowledge of dangerous substances, ignition sources, zoning, and control measures, as required by UK health and safety law.

At Fire Risk Assessment Network, we regularly carry out and review DSEAR risk assessments for organisations ranging from offices and retail premises to workshops, warehouses, and industrial environments.

In practice, we often see DSEAR risks overlooked because dangerous substances are considered “incidental” to the business rather than integral to daily operations. Our approach focuses on:

• Identifying real ignition and explosion risks, not theoretical ones
• Ensuring zoning and equipment selection are proportionate and justified
• Aligning DSEAR controls with wider fire and health & safety management
• Producing clear, defensible findings that support compliance and safe operation

Need a Trusted DSEAR Risk Assessment Service?

Our competent assessors provide practical, compliant DSEAR risk assessments that help organisations meet their legal duties and manage risk effectively.

We can support you by:

• Carrying out your DSEAR risk assessment
• Reviewing existing assessments
• Advising on zoning, control measures, and equipment suitability
• Supporting ongoing compliance and review planning

If you would like to discuss your DSEAR obligations or book an assessment, contact us today.

A DSEAR risk assessment should be reviewed where substances, processes, equipment, storage arrangements, or building layouts change, or where there is reason to believe existing controls may no longer be effective.

Conclusion

DSEAR applies to a far wider range of workplaces than is often assumed, including many environments where dangerous substances are used only incidentally as part of everyday operations.

A suitable and sufficient DSEAR risk assessment allows employers to identify where fire, explosion, or corrosion risks may arise, and to implement proportionate controls that protect people, property, and business continuity. Where assessments are missing, outdated, or based on assumptions rather than actual risk, organisations may be exposed to enforcement action and avoidable incidents.

Regular review is essential, particularly where substances, processes, layouts, or equipment change. Where there is uncertainty about the scope or adequacy of existing arrangements, professional assessment and advice can provide clarity and assurance that DSEAR duties are being met.

Frequently Asked Questions About DSEAR Risk Assessments

What is a DSEAR risk assessment?

A DSEAR risk assessment is an assessment required under the Dangerous Substances and Explosive Atmospheres Regulations 2002 to identify and control risks from dangerous substances that could cause fire, explosion, or corrosion of metal. It focuses on ignition sources, explosive atmospheres, zoning, and appropriate control measures.

Does DSEAR apply to all workplaces?

DSEAR applies to most workplaces, not just industrial or manufacturing environments. Many offices, retail premises, workshops, warehouses, and commercial buildings contain dangerous substances such as flammable liquids, gases, aerosols, or combustible dusts as part of normal operations.

Is a DSEAR risk assessment a legal requirement?

Yes. Where dangerous substances are present or could be present, employers and those in control of premises have a legal duty to assess and control the risks under DSEAR. This duty is enforced by the Health and Safety Executive.

Who can carry out a DSEAR risk assessment?

A DSEAR risk assessment must be carried out by a competent person with sufficient knowledge of dangerous substances, ignition sources, hazardous area zoning, and control measures. The assessor must be able to identify real risks and recommend proportionate, practical controls.

What is the difference between DSEAR and COSHH?

COSHH focuses on health risks from hazardous substances, while DSEAR specifically addresses fire, explosion, and corrosion risks. In many workplaces, both regulations apply and should be considered together, but a COSHH assessment does not replace a DSEAR risk assessment where explosive or flammable hazards exist.

What are DSEAR zones and why are they important?

DSEAR zones classify areas where explosive atmospheres may occur. Correct zoning (Zones 0–2 for gases/vapours and Zones 20–22 for dusts) is essential for selecting suitable equipment and ensuring ignition sources are adequately controlled.

How often should a DSEAR risk assessment be reviewed?

A DSEAR risk assessment should be reviewed whenever there are changes to substances used, processes, storage arrangements, equipment, or building layout, or where there is reason to believe existing controls may no longer be effective. Regular review also supports ongoing legal compliance.

Do small businesses need a DSEAR risk assessment?

Yes, if dangerous substances are present or could be present. DSEAR duties are risk-based, not size-based. Even small businesses may require a DSEAR risk assessment where flammable substances, gases, or dusts are used or stored.