Understanding DSEAR and ATEX: Managing Fire and Explosion Risks
- Alessandro Capaldi | Department Manager, Senior Consultant
- 3 days ago
- 5 min read
In this article:
Key takeaways
DSEAR provides the UK legal framework for managing risks from dangerous substances and explosive atmospheres, and transposes the EU ATEX 153 Workplace Directive (1999/92/EC) into UK law.
ATEX distinguishes between workplace safety and equipment compliance, with ATEX 153 (DSEAR equivalent) addressing explosion risk management and ATEX 114 governing the design and certification of equipment for use in explosive atmospheres.
The regulations require a risk-based, proportionate approach, aligned with principles of inherently safer design and ALARP.
Effective DSEAR and ATEX compliance goes beyond hazardous area classification and paperwork - it depends on integrated technical, procedural and organisational controls.
DSEAR and ATEX apply across the full lifecycle of facilities, including design, modification, operation, maintenance and decommissioning.
What is DSEAR?
Across all sectors, organisations work continuously to manage the risks associated with the hazardous materials they use or produce; even so, fire and explosion hazards remain among the most significant contributors to high‑consequence events. The Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) 2002 is the UK’s primary piece of legislation regulating the control of substances capable of causing fire or explosions within the workplace.
The aim of DSEAR is to eliminate, or reduce to as low as reasonably practicable (ALARP), the risk of fires and explosions in the workplace, in order to protect employees, visitors, and members of the public who may be affected. Adherence to DSEAR also complements risk management measures required by The Health and Safety at Work Act 1974 and the Management of Health and Safety at Work Regulations 1999.
DSEAR vs ATEX
ATEX (short for ATmosphères EXplosibles) is a collective term for European legislation governing safety in explosive atmospheres. While the UK no longer operates under EU directives, ATEX remains a useful reference point for understanding how DSEAR fits within the wider regulatory landscape.
ATEX comprises two separate directives, each with a distinct focus:
ATEX 153 (1999/92/EC) – Workplace safety: This directive places duties on employers to assess explosion risks, classify hazardous areas, and implement appropriate technical and organisational controls to protect workers.
ATEX 114 (2014/34/EU) – Equipment and protective systems: This is a product regulation, setting essential health and safety requirements for equipment intended for use in potentially explosive atmospheres. It applies to manufacturers and suppliers, not employers, and governs how equipment is designed, certified and placed on the market.
In the UK, DSEAR is the direct equivalent of ATEX 153. It transposes the workplace safety principles of the ATEX regime into UK law, requiring employers to identify dangerous substances, assess fire and explosion risks, and reduce those risks to ALARP across the full lifecycle of an activity or installation. However, DSEAR does not replace ATEX 114.
When is DSEAR and ATEX Required?
Compliance with DSEAR is required for any workplace in where dangerous substances are present, used, or produced. In contrast, ATEX 153 applies where such substances may give rise to potentially explosive atmospheres which may arise in such quantities as to endanger the health and safety of workers or others, i.e. where flammable gases, vapours, mists, or dusts could form mixtures with air capable of ignition. For the purposes of these regulations, a workplace is defined as any premises, or section of a premises, in which work is carried out by an employer or self-employed person. Workplaces may be, but are not limited to, industrial or commercial premises, onshore facilities or offshore installations, vehicles and vessels, or construction sites.
A substance or mixture may be considered dangerous if it creates a risk to personal safety from fire, explosion, or other similar energetic events, or if it is corrosive to metals. Substances capable of causing energetic events with physical effects similar to those of fire and explosion, such as thermal radiation, over‑pressurisation, and oxygen depletion are also covered by DSEAR.
What are “Dangerous Substances”?
A dangerous substance is any substance that could cause harm due to fire, explosion, or similar energetic events. This includes:
Flammable gases, vapours, mists and liquids;
Combustible dusts and fibres;
Explosives and oxidising substances; and
Substances that can form explosive atmospheres with air.
Crucially, DSEAR applies regardless of quantity, but the level of action required depends on the actual risk. Small inventories, transient releases, maintenance activities and non‑routine operations can all present significant risk if not properly managed. In contrast, ATEX 153 applies only where such conditions may give rise to a potentially explosive atmosphere; while this is also risk-based and not subject to fixed quantity thresholds, applicability depends on the likelihood that flammable gases, vapours, mists, or dusts can form an ignitable mixture with air under atmospheric conditions.
What Activities May Require Compliance with DSEAR or ATEX?
Companies carrying out any of the following activities are likely to be required to comply with DSEAR (UK) or ATEX (EU):
Storage of fuels;
Use of flammable gases or solvents;
Handling and storage of waste dust;
‘Hot work’, such as welding, on vessels that have contained flammable material or substances;
Work that may result in the release of naturally occurring flammable substances;
Handling, storing, or transporting flammable substances;
Chemical manufacturing, processing, or storage;
Handling, storage, and use of gases under pressure; and
Handling, storage, and use of substances corrosive to metals.
DSEAR and ATEX Compliance
DSEAR places a requirement on employers to assess the risks from dangerous substances and take the required measures to eliminate or reduce these risks to ALARP levels. ATEX requires employers to protect against where explosive atmospheres may arise in sufficient quantities as to endanger the health and safety of workers or others. To ensure full compliance with both DSEAR and ATEX the following steps should be carried out:
Assess Risks: A risk assessment should be conducted to catalogue and examine all dangerous substances present at the premises, and any activities involving these substances. This risk assessment should evaluate the potential for fire, explosion, or other energetic events under DSEAR, and specifically the likelihood and persistence of potentially explosive atmospheres under ATEX.
Prevent or Control Risks: Where risks related to dangerous substances have been identified, best practice is to eliminate the risk by substituting a less dangerous substance or work process. Where this is not reasonably practicable, measures must be taken to control the risk and reduce its severity should it be realised.
Use Control Measures: If elimination of risks is not possible then control measures consistent with the risk assessment and appropriate to the activities or operations being conducted should be undertaken. Areas where explosive atmospheres may occur should be identified and classified into zones based on the likelihood and duration of occurrence, forming the basis for equipment selection and control measures.
Mitigate: Where elimination is not possible, mitigation measures should be in place alongside control measures to reduce the consequences of any fire or explosion that does occur.
Prepare Emergency Plans and Procedures: Plans and procedures should be proportional to the risk posed and available and published to all those who might be affected by the risk. For ATEX compliance, this should be supported by an Explosion Protection Document demonstrating the assessment of explosion risks, hazardous area classification, and control measures in place.
Provide Employee Training and Instruction: Workers should be provided with relevant information and training regarding dangerous substances and the associated risks, the findings of the risk assessment, the control measures in place, and emergency procedures.
Conclusion
DSEAR and ATEX provide a powerful and flexible framework for managing fire and explosion risks, but its effectiveness depends entirely on how rigorously it is applied. For organisations seeking not only compliance but robust risk assessment and reduction, DSEAR and ATEX represent an opportunity to embed stronger, more systematic controls into their operations.
Do you need any support carrying out a DSEAR or ATEX risk assessment or ensuring DSEAR/ATEX compliance within the workplace? Reach out to ORS and we will guide you in the process.
