Workplaces have long managed health risks from hazardous substances under COSHH. DSEAR exists because fire and explosion are a different category of risk entirely, one that needed its own legal framework.
UK employers handling flammable liquids, combustible dusts, or pressurised gases face a distinct set of legal duties separate from general chemical exposure rules. These duties cover the risk of fire, explosion, and metal corrosion, not the health effects of breathing in or touching a substance.
DSEAR stands for the Dangerous Substances and Explosive Atmospheres Regulations 2002. It requires employers to assess and control the risks to safety, not health, from dangerous substances present in the workplace (HSE).
This article covers what counts as a dangerous substance under DSEAR, what the regulations require employers to do, and how DSEAR differs from COSHH.
Key Takeaways
- DSEAR stands for the Dangerous Substances and Explosive Atmospheres Regulations 2002, in force since 9 December 2002.
- DSEAR addresses risks to safety from fire, explosion, and corrosion of metal, separately from COSHH, which addresses health risks from exposure.
- Since June 2015, DSEAR also covers substances corrosive to metals and gases under pressure.
- Employers with five or more employees must record the major findings of any DSEAR risk assessment.
- DSEAR requires hazardous areas to be classified into zones under Schedule 2, linked to the ATEX equipment regulations.
- The Approved Code of Practice for DSEAR is published by the HSE as L138.
- A DSEAR risk assessment must be reviewed and updated when conditions change or after an incident.
What Does DSEAR Stand For?
DSEAR stands for the Dangerous Substances and Explosive Atmospheres Regulations 2002. It came into force on 9 December 2002 and applies to nearly every workplace in the UK where dangerous substances are present (HSE, Edinburgh).
The regulations place duties on employers and the self-employed to protect workers and members of the public from risks to safety caused by fire, explosion, or corrosion of metal. DSEAR complements the Management of Health and Safety at Work Regulations 1999, applying that general duty specifically to dangerous substances (HSE).
DSEAR was introduced to implement the EU's ATEX Directive into UK law. It works alongside the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 1996, which sets certification requirements for equipment used in explosive environments (Spiers Safety).
A dangerous substance under DSEAR is any substance or preparation that is explosive, flammable, highly flammable, or oxidising, or that creates a risk because of its physicochemical properties, how it is used, or its presence in the workplace. Dust capable of forming an explosive atmosphere when mixed with air falls within scope as well.
What Counts as a Dangerous Substance Under DSEAR?
Dangerous substances appear in nearly every type of workplace, not only chemical plants. Common examples include:
- Solvents, paints, and varnishes used in manufacturing or maintenance
- Flammable gases, including liquid petroleum gas (LPG)
- Dusts from machining, sanding, or woodworking operations
- Combustible dusts from foodstuffs, including flour and sugar
- Pressurised gases stored in cylinders or process lines
- Substances corrosive to metals
Since June 2015, DSEAR has also covered gases under pressure and substances corrosive to metals, expanding the scope beyond the original 2002 list. HSE expected the practical impact of this change to be limited, since the underlying hazards of these substances had not changed, only the formal requirement to assess them under DSEAR (HSE, L138).
What Must Employers Do Under DSEAR?
DSEAR sets out specific actions employers must take wherever dangerous substances are manufactured, stored, processed, or used.
- Carry out a risk assessment of any work activity involving dangerous substances, covering the substance itself, the quantity present, and the work process.
- Identify and classify hazardous areas where explosive atmospheres may occur, dividing them into zones as defined in Schedule 2 of DSEAR.
- Eliminate or control ignition sources within classified zones, including unprotected electrical equipment that is not ATEX-rated.
- Provide technical and organisational controls to eliminate or reduce identified risks as far as reasonably practicable, following the DSEAR hierarchy: elimination or substitution, avoidance of release, control at source, and prevention of ignition.
- Verify explosion safety before a hazardous area is used for the first time, using a person competent in explosion protection.
- Record major findings where five or more employees are present, including the substances identified, the risks they pose, and the control measures in place.
- Provide information and training proportionate to the level of risk, so workers understand the hazards and the controls protecting them.
A DSEAR risk assessment depends on accurate substance data, flashpoints, explosive limits, storage volumes, pulled straight from the SDS. A risk assessment tool built around your SDS library keeps that data linked, so assessments stay current as substances or SDS versions change, rather than relying on a static spreadsheet built once and forgotten.
How Does DSEAR Differ From COSHH?
DSEAR and COSHH are frequently confused because both apply to hazardous substances, but they address different types of harm.
DSEAR deals with the immediate danger to life or health arising from fire, explosion, or the ignition of dangerous substances. It governs safety risks: the sudden, energetic events that follow when a flammable or explosive substance ignites.
COSHH deals with the chronic and acute health effects of exposure to substances hazardous to health, such as respiratory disease, skin sensitisation, or poisoning from inhalation or contact. It governs ongoing exposure, not ignition events.
Overlap in practice: Many substances fall under both regulations at once. A solvent that is both flammable and capable of causing respiratory irritation requires a DSEAR assessment for the fire and explosion risk and a separate COSHH assessment for the health risk. The two assessments draw on the same Safety Data Sheet but answer different questions.
Both regulations rely on accurate, current SDS data. Where a chemical warehouse safety programme already tracks flashpoints, storage volumes, and ATEX zone requirements for DSEAR, the same SDS data feeds directly into the COSHH risk assessment for the same substances.
Final Thoughts
DSEAR is not a one-time exercise completed when a substance first enters the workplace. Risk assessments need review whenever conditions change, equipment is added, or an incident occurs. Hazardous area classifications drawn up years ago may no longer reflect current storage volumes or process layouts.
The starting point for most workplaces is the same: knowing which substances on site are dangerous under DSEAR, understanding their flashpoint and explosive properties from the SDS, and confirming which areas require zone classification. Keeping that SDS information accessible and current makes both the DSEAR assessment and the parallel COSHH assessment easier to maintain over time.
Frequently Asked Questions
What does DSEAR stand for?
DSEAR stands for the Dangerous Substances and Explosive Atmospheres Regulations 2002, the UK regulation governing fire, explosion, and metal corrosion risks from dangerous substances in the workplace.
What is the difference between DSEAR and COSHH?
DSEAR addresses safety risks from fire, explosion, and corrosion. COSHH addresses health risks from exposure to hazardous substances. A single substance can require both a DSEAR and a COSHH assessment.
Who needs to comply with DSEAR?
Any employer or self-employed person whose work activities involve dangerous substances must comply with DSEAR, regardless of business size or sector, including higher education and small businesses.
What is a DSEAR zone?
A DSEAR zone is an area classified under Schedule 2 of DSEAR where an explosive atmosphere may occur in quantities requiring special precautions, linked to ATEX equipment certification requirements.
Does DSEAR apply to combustible dust?
Yes. Dust from machining, sanding, or food processing that can form an explosive atmosphere when mixed with air falls within the scope of DSEAR.
Mehreen Iqbal
Started with a Bachelors in Microbiology, then a Masters in Public Health; Currently a Workplace Safety Expert.