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DSEAR Explained for Business Owners & Responsible Persons

As a business owner, employer, or self-employed individual in the UK, it is important to know at least the basics on DSEAR or Dangerous Substances and Explosive Atmospheres Regulations.

Definitions: DSEAR, Dangerous Substances, Explosive Atmospheres


The Dangerous Substances and Explosive Atmospheres Regulations 2002 is the primary legislation that applies to the control of substances that can cause workplace fires and explosions. DSEAR places responsibility on employers and the self-employed to protect people who may be put at risk to fire and explosions in the workplace. These include not just employees but also visitors and members of the public.

Dangerous Substances

Dangerous Substances are the substances or mixtures of substances (referred to as “preparations” in DSEAR) that have the potential to cause harm to people through fire, explosions, or metal corrosion. Liquids, gases, and combustible dusts that are in the workplace that could cause these events when not properly controlled are all considered dangerous substances. These include the following:

  • petrol
  • paints
  • solvents
  • varnishes
  • gas oil and light heating oils
  • flammable gases (i.e., liquid petroleum gas)
  • pressurised gases
  • dusts from machining and sanding operations
  • dusts from foodstuffs

Explosive Atmospheres

Under the DSEAR, an explosive atmosphere refers to when dangerous substances mix with air under ambient pressures and temperatures, and if ignition occurs, combustion will spread out into the whole mixture. It doesn’t necessarily mean that an explosion will occur each time an explosive atmosphere is created. However, if a fire occurs in an explosive atmosphere, such fire will move and spread very rapidly.

A workplace may have spaces or activities that create explosive atmospheres or potentially explosive atmospheres. Examples of such spaces include but are not limited to warehouses, silos, refineries, and construction sites. Some workplaces may not seem to fall under this category at first glance but may have activities that can create potential explosive atmospheres.

DSEAR Requirements for Employers

The DSEAR places the responsibility on employers to assess, then eliminate or reduce the risks from dangerous substances. The self-employed are considered employers for compliance purposes of the DSEAR.

Compliance to the Regulations involves:

Risk assessment

This includes

  • identifying dangerous substances in the workplace
  • identifying work activities that involve these substances
  • identifying workplace areas of potential explosive atmospheres
  • identifying how these substances and work activities can cause harm

No further action is needed if risk is found to be negligible or trivial. If there are significant findings in the risk assessment, the employer must record these findings and examine what else they need to do to comply with the DSEAR. 

These may include some or all of the actions that follow.

Risk prevention

The best risk prevention measure is to eliminate the risk entirely by either replacing the dangerous substance or using an alternative work process, if possible. In situations or industries where changing the substance or work process is not possible, employers must then apply measures to control the risks and mitigate the effects if a harmful event does occur.

  • Control, Mitigation and Emergency procedures

These procedures to control, mitigate and address emergency situations should be consistent with the risk assessment and match the nature of the work activity.

The DSEAR requires employers to put controls in place where dangerous substances and their risks cannot be eliminated. These controls should reduce the effects if an incident occurs involving these substances, and are to be applied in the following order:

  • store only the minimum amount of dangerous substances in the workplace
  • minimise the release of dangerous substances if it can’t be avoided
  • control the release of dangerous substances at their source
  • prevent dangerous or explosive atmospheres from forming
  • collect, contain, and remove any substance release to a safe area (example: use of ventilation)
  • eliminate sources of ignition
  • steer clear from creating opportunities that would lead to dangerous conditions (example: going past the maximum settings for temperatures)
  • store incompatible substances separately

Mitigation procedures are also required by the DSEAR in addition to the controls put in place. These procedures include:

  • scaling down the number of employees exposed to the risk
  • providing plants that are resistant to explosion and corrosion
  • having equipment for explosion suppression or relief on hand
  • having the means and steps to control or minimise explosions or spread of fires
  • providing sufficient personal protective equipment

Plans and procedures for emergencies must also be implemented. These include safety drills, warning systems, communication systems, etc that are in proportion to the possible risks. These emergency plans and procedures must be relayed to emergency services.

Workers assigned to carry out repairs and other work during an emergency should be provided with the proper equipment for doing such work safely.

Information dissemination and Training

Employers must make sure that staff are properly informed and given instructions and sufficient training to deal with the risks associated with dangerous substances.

Information and training include

  • information on which dangerous substances are present in the workplace, their associated risks, safety data sheets, and other legislation applicable on these dangerous substances
  • identifying contents of pipes, containers, and the like so staff and other people are informed of their presence
  • risk management findings
  • control measures that are in place
  • procedures to follow if an emergency occurs

Non-employees (visitors and other people) don’t need to be provided information and training unless it is required and proportionate to the level and type of risk.

Frequently Asked Questions

Does my business require a DSEAR Assessment?

A DSEAR Assessment is required if a dangerous substance is present in your workplace and if certain types of activities or work are being carried out that present a safety risk.

As listed in the Health and Safety Executive website the following illustrate the type of activities covered by DSEAR:

  • storage of petrol (for cars, boats, horticultural machinery)
  • use of flammable gases (for example, acetylene for welding)
  • handling and storage of waste dusts (for example, in the manufacturing industry)
  • handling and storage of flammable wastes (for example, fuel oils)
  • welding or doing other ‘hot work’ on drums and tanks that have contained flammable material
  • work that could release naturally occurring flammable substances such as methane (for example, in coal mines and landfill sites)
  • use of flammable solvents (for example, in laboratories)
  • storage and display of flammable goods (for example, paints in shops)
  • filling, storing and handling aerosols with flammable propellants (for example, LPG)
  • transporting containers with flammable substances from one location to another within the workplace
  • deliveries from road tankers (for example, petrol and bulk powders)
  • manufacturing, processing, and warehousing of chemicals
  • petrochemical industry (both onshore and offshore)
  • handling, storing, and using gases under pressure
  • handling, storing, and using substances that are corrosive to metal.

Will I still need the DSEAR Risk Assessment if I already have a Fire Risk Assessment?

Both the DSEAR Risk Assessment and the Fire Risk Assessment deal with the risk of fires and explosions. However, the DSEAR Risk Assessment is specific to dangerous substances and their subsequent effect on the fire precautions and safety requirements that would be required of your business. A Fire Risk Assessment may identify if there is a need for a DSEAR Risk Assessment, you can find more details on our Fire Risk Assessment services here

Are the DSEAR Risk Assessment and Fire Risk Assessment reviews required at the same time?

The reviews on both will depend on the level of risk and with how much the activities in your workplace have changed. Other significant changes including an accident or dangerous event will also merit a review.


Get in touch to find out more or book your DSEAR Risk Assessment or FRA here.


UK Gov HSE Articles DSEAR, DSEAR Background, Atex