DSEAR 2002: HSE Explosive Atmospheres Rules

Regulatory citation: Dangerous Substances and Explosive Atmospheres Regulations 2002 (SI 2002/2776)

What Is DSEAR?

The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) require employers and the self-employed in Great Britain to control the risks to safety from fire, explosions and substances corrosive to metals. Dangerous substances include solvents, paints, flammable gases such as LPG, combustible dusts and pressurized gases.

Why DSEAR Matters

Fires and explosions involving flammable vapors or combustible dusts can injure workers and the public and destroy buildings in seconds.

Core Requirements

1. Assess the Risks (Regulation 5)

Where a dangerous substance is or may be present, employers must carry out a suitable and sufficient risk assessment covering how it is used and stored, the likelihood of an explosive atmosphere and ignition, and the likely scale of a fire or explosion. Employers with five or more employees must record the significant findings. New work with a dangerous substance can't start until this is done.

2. Eliminate or Reduce Risks (Regulation 6)

Risks must be eliminated or reduced so far as reasonably practicable, with substitution preferred. Remaining risks must be controlled (for example by minimizing quantities, preventing releases and avoiding ignition sources) and their effects mitigated, for example with explosion relief.

3. Classify Hazardous Areas Into Zones (Regulation 7)

Places where explosive atmospheres may occur must be classified as hazardous or non-hazardous, and hazardous places divided into zones based on how often and how long an explosive atmosphere is present: Zones 0, 1 and 2 for gases, vapors and mists, and Zones 20, 21 and 22 for combustible dusts.

4. Use Suitable Equipment

Equipment and protective systems in zoned areas must be selected by category: Category 1 in Zone 0 or 20, Category 1 or 2 in Zone 1 or 21, and Category 1, 2 or 3 in Zone 2 or 22. New equipment should meet the ATEX-based Equipment and Protective Systems Regulations 2016.

5. Mark Zone Entry Points and Verify Safety

Where necessary, entry points to zoned areas must be marked with the specified EX warning sign. Before first use, a person competent in explosion protection must verify overall explosion safety.

6. Plan for Emergencies and Train Workers (Regulations 8 and 9)

Employers must prepare emergency procedures, warning systems and tested safety drills, and share relevant information with emergency services, unless the risk is only slight. Employees must receive information, instruction and training on the dangerous substances and the precautions in place.

Common Compliance Approaches

Hazardous Area Drawings

Keep zone drawings current and use them to control equipment and work in each area.

Control Ignition Sources

Use hot work permits and manage static through earthing and bonding.

Use HSE's Approved Code of Practice

HSE's ACOP L138 gives practical guidance on meeting DSEAR.

Example: DSEAR in Practice

A furniture finisher uses solvent-based lacquers in a spray booth. After its DSEAR assessment, it switches some products to water-based coatings, reduces the solvent kept in the booth, zones the booth and extraction ducting, fits suitably categorized lighting and fans, marks the entrance with the EX sign and trains sprayers.

Related regulations: HSE COSHH, MHSWR risk assessments, OSHA Welding, Cutting and Hot Work.

Note: This summary reflects the regulations as they apply in Great Britain, enforced by the Health and Safety Executive (HSE) and local authorities. Northern Ireland has equivalent but separate legislation. Always check the current legislation and HSE guidance.

Frequently Asked Questions

What is a DSEAR risk assessment?

It is an assessment of the fire and explosion risks from dangerous substances at work and the measures needed to control them. Employers with five or more employees must record the significant findings.

What are DSEAR zones?

Zones describe how likely an explosive atmosphere is. For gases and vapors, Zone 0 means it is present continuously or for long periods, Zone 1 means it is likely occasionally in normal operation, and Zone 2 means it is unlikely and short-lived. Zones 20, 21 and 22 are the equivalents for combustible dust.

Does DSEAR apply to small quantities of flammable substances?

Yes, but measures should be proportionate. Where the risk is only slight because of the small quantities involved, the emergency arrangement requirements do not apply.