DSEAR Compliance Guide: Your Legal Obligations for Explosive Atmospheres
What is DSEAR and what are your legal obligations? This guide explains the Dangerous Substances and Explosive Atmospheres Regulations, risk assessment requirements, and how to achieve compliance.
DSEAR and Your Legal Responsibilities
If your workplace handles flammable gases, combustible dusts, or any dangerous substances that could create an explosive atmosphere, you have legal obligations under DSEAR—the Dangerous Substances and Explosive Atmospheres Regulations 2002.
These aren't optional guidelines. DSEAR is UK law, enforced by the Health and Safety Executive, with serious penalties for non-compliance. More importantly, the risks DSEAR addresses are real: explosive atmosphere incidents can cause fatalities, life-changing injuries, and devastating property damage.
This guide explains what DSEAR requires, who it applies to, and how to meet your obligations. Whether you're new to DSEAR or reviewing your current compliance, this is the information you need.
What is DSEAR?
DSEAR stands for the Dangerous Substances and Explosive Atmospheres Regulations 2002. It's the UK legislation that implements the European ATEX Workplace Directive (1999/92/EC) and also covers the chemical safety aspects of dangerous substances more broadly.
Read our full guide here on ATEX industrial vacuums
The regulations require employers to control the risks from fire and explosion caused by dangerous substances in the workplace. A dangerous substance under DSEAR is any substance or mixture that could create a risk from energetic (explosive) events or thermal (fire) events.
This includes:
Flammable gases (natural gas, propane, hydrogen, acetylene)
Flammable liquids and their vapours (petrol, solvents, paints, adhesives)
Flammable solids (certain metals, chemicals)
Combustible dusts (flour, wood dust, metal powders, pharmaceutical ingredients)
Substances that react dangerously with water or air
Any other substance that could cause an explosive atmosphere
If any of these are present in your workplace—even in small quantities—DSEAR almost certainly applies to you.
Does DSEAR Apply to Your Workplace?
DSEAR applies to most workplaces. The scope is deliberately broad because dangerous substances are common in everyday operations.
You're almost certainly covered if you:
Store or use flammable liquids (including cleaning solvents, fuels, paints)
Handle materials that create combustible dust (food ingredients, wood, metals, pharmaceuticals)
Use or store LPG, natural gas, or other flammable gases
Operate processes that could release flammable vapours
Work in industries like manufacturing, food production, woodworking, pharmaceuticals, chemicals, or waste processing
Even offices with a small quantity of aerosols or cleaning chemicals technically fall under DSEAR, though the required controls would be proportionate to the low risk level.
DSEAR does not apply to ships, below-ground mining activities (covered by separate regulations), medical treatment of patients, or domestic premises. But if you're reading this guide, your workplace almost certainly requires some level of DSEAR compliance.
Your Legal Obligations Under DSEAR
DSEAR places specific duties on employers. These aren't suggestions—they're legal requirements with potential criminal penalties for non-compliance.
Risk Assessment (Regulation 5)
You must carry out a suitable and sufficient assessment of the risks from dangerous substances. This assessment must identify:
The dangerous substances present or likely to be present
The fire and explosion hazards they create
Who might be harmed and how
The likelihood and potential severity of incidents
The assessment must be recorded if you have five or more employees, and must be reviewed regularly or when circumstances change.
Elimination or Reduction of Risks (Regulation 6)
Based on your risk assessment, you must eliminate risks where possible, or where elimination isn't reasonably practicable, reduce them to an acceptable level. The hierarchy of controls is:
Reduce the quantity of dangerous substances to a minimum
Avoid or minimise releases of dangerous substances
Control releases at source
Prevent the formation of explosive atmospheres
Collect, contain, and remove releases to a safe place
Avoid ignition sources and adverse conditions
Segregate incompatible substances
Hazardous Area Classification (Regulation 7)
Where explosive atmospheres may occur, you must classify hazardous places into zones based on the likelihood and duration of the explosive atmosphere. These zones directly determine what equipment can be used in each area. [LINK: ATEX Zone Classifications Explained]
Equipment and Protective Systems (Regulation 7)
Equipment used in hazardous areas must be suitable for the zone classification. This means using ATEX-certified equipment that's rated for the specific zone where it will operate. Using incorrectly rated equipment is a breach of DSEAR.
Emergency Arrangements (Regulation 8)
You must prepare procedures and provide equipment to deal with accidents, incidents, and emergencies related to dangerous substances. This includes warning and communication systems, escape facilities, and information for emergency services.
Information, Instruction, and Training (Regulation 9)
Workers must receive appropriate information, instruction, and training on the risks they face and the precautions required. This must be updated to reflect new or changed risks.
The DSEAR Risk Assessment Process
A DSEAR risk assessment isn't a tick-box exercise. It requires genuine analysis of your workplace and processes. Here's a practical approach:
Step 1: Identify dangerous substances.
Survey your workplace for all substances that could create fire or explosion hazards. Don't forget dusts from processes—many common materials become explosive when dispersed in air. Check safety data sheets, but also consider substances generated by your processes. [LINK: Complete Guide to Combustible Dusts]
Step 2: Identify where explosive atmospheres could form.
For each dangerous substance, consider where releases could occur and where they could accumulate to form an explosive mixture. Consider normal operations, maintenance activities, and foreseeable abnormal conditions.
Step 3: Identify ignition sources.
Map all potential ignition sources in areas where explosive atmospheres could form. These include electrical equipment, hot surfaces, flames, mechanical sparks, static electricity, and even lightning. Standard industrial equipment—including vacuum cleaners—can be ignition sources. [LINK: ATEX vs Standard Industrial Vacuums]
Step 4: Evaluate the risks.
Consider the likelihood of an explosive atmosphere forming, the likelihood of an ignition source being present at the same time, and the potential consequences. This evaluation drives your control measures and zone classifications.
Step 5: Determine control measures.
Apply the hierarchy of controls to eliminate or reduce risks. This typically includes prevention of releases, ventilation, housekeeping, zone classification, and appropriate equipment selection.
Step 6: Document and review.
Record your assessment, including the zones you've classified and the equipment required. Review regularly—the HSE suggests at least annually—and whenever processes or substances change.
DSEAR Zone Classifications
Zone classification is a critical output of your DSEAR assessment. The zones you assign directly determine what equipment is legally permitted in each area.
For gases, vapours, and mists:
Zone 0: Explosive atmosphere present continuously or for long periods
Zone 1: Explosive atmosphere likely to occur occasionally in normal operation
Zone 2: Explosive atmosphere not likely in normal operation, but if it does occur, will persist for a short period
For combustible dusts:
Zone 20: Explosive dust cloud present continuously or for long periods
Zone 21: Explosive dust cloud likely to occur occasionally in normal operation
Zone 22: Explosive dust cloud not likely in normal operation, but if it does occur, will persist for a short period
Understanding these classifications and correctly applying them to your workplace is essential for DSEAR compliance. Our detailed guide covers this in depth. [LINK: ATEX Zone Classifications Explained]
Equipment Requirements Under DSEAR
Once you've classified your hazardous areas, you must ensure that all equipment used in those areas is appropriately rated. This isn't just about major installations—it includes portable equipment like vacuum cleaners, which are frequently used in areas where combustible dusts are present.
Equipment for use in hazardous areas must:
Be certified to ATEX standards (or equivalent)
Be rated for the zone classification where it will be used
Be suitable for the specific gas group or dust group present
Have an appropriate temperature classification
Be properly maintained and inspected
Using standard (non-ATEX) equipment in a classified zone is a breach of DSEAR. It's also extremely dangerous—standard equipment can provide the ignition source for a catastrophic explosion. [LINK: ATEX Vacuum Buying Guide]
Enforcement and Penalties
DSEAR is enforced by the Health and Safety Executive (HSE) and local authorities. Inspectors can visit your premises, examine your DSEAR assessment, check your zone classifications, and verify that appropriate equipment is in use.
Enforcement actions can include:
Improvement notices: Requiring you to take specific actions within a set timeframe
Prohibition notices: Stopping dangerous activities immediately
Prosecution: Criminal charges for serious breaches, with unlimited fines and potential imprisonment
Beyond regulatory penalties, DSEAR breaches can result in civil liability if workers or others are harmed, insurance policy voidance, and devastating reputational damage following an incident.
Getting Compliant: Practical Steps
If you haven't yet addressed DSEAR compliance, or you're unsure whether your current arrangements are adequate, here's how to move forward:
Conduct or review your DSEAR risk assessment. If you don't have one, this is your first priority. If you have one, check when it was last reviewed and whether it reflects current operations.
Verify your zone classifications. Ensure that all areas where explosive atmospheres could form have been classified. Review the boundaries—zones can change if processes change.
Audit your equipment. Check every piece of equipment used in classified zones. Look for ATEX markings and verify they're appropriate for the zone. Pay particular attention to cleaning equipment—industrial vacuums are a common weak point.
Address any gaps. Replace or remove non-compliant equipment. Implement additional controls where needed. Update procedures and training.
Document everything. Keep records of your assessment, zone classifications, equipment in use, maintenance, and training. These records demonstrate compliance and are essential if an inspector visits.
DSEAR Compliance Support
Selecting the right ATEX-certified equipment is a key part of DSEAR compliance. CFM North East has over 25 years of experience helping UK businesses meet their obligations with properly rated industrial cleaning equipment.
As an approved Nilfisk supplier, we provide ATEX industrial vacuums for Zone 1/21 and Zone 2/22 applications, along with expert guidance on matching equipment to your zone classifications.
Whether you need help understanding your equipment requirements or you're ready to specify compliant vacuums for your hazardous areas, we can help.
