DSEAR refers to the Dangerous Substances and Explosive Atmospheres Regulations 2002. Dangerous substances can put peoples' safety at risk from fire and explosion. DSEAR puts duties on employers and the self-employed to protect people from risks to their safety from fires, explosions and similar events in the workplace, this includes members of the public who may be put at risk by work activity.


"Dangerous Substance":

  1. A substance or preparation which meets the criteria in the approved classification and labelling guide for classification as a substance or preparation which is explosive, oxidising, extremely flammable, highly flammable or flammable, whether or not that substance or preparation is classified under the CHIP/CLP Regulations;
  2. A substance or preparation which because of its physico-chemical or chemical properties and the way it is used or is present at the workplace creates a risk, not being a substance or preparation falling within subparagraph (1) above;
  3. Or any dust, whether in the form of solid particles or fibrous materials or otherwise, which can form an explosive mixture with air or an explosive atmosphere, not being a substance or preparation falling within subparagraphs (a) or (b) above.

Includes any substance or preparation which, because of its properties or the way it is used, could cause harm to people from fires and explosions. Dangerous substances include those with potential energy releasing events similar to fire and explosion such as exothermic reactions. Examples include: petrol; liquefied petroleum gas (LPG); paints; varnishes; solvents; and dusts which when mixed with air could cause an explosive atmosphere (eg dusts from milling and sanding operations)

"Explosive Atmosphere"

Means a mixture, under atmospheric conditions, of air and one or more dangerous substances in the form of gases, vapours, mists or dusts which, after ignition has occurred, combustion spreads to the entire unburned mixture.


The following documents in respect of DSEAR are available in the Document Library:

  • F008 DSEAR Risk Assessment

For further information relating to any of these documents, please contact the Health, Safety and Environment Team at hasstaff@aber.ac.uk or on extension 2073.

What does DSEAR require?

Departments must:

  • find out what dangerous substances are in their workplace and what the fire and explosion risks are;
  • put control measures in place to either remove those risks or, where this is not possible, control them;
  • put controls in place to reduce the effects of any incidents involving dangerous substances;
  • prepare plans and procedures to deal with accidents, incidents and emergencies involving dangerous substances;
  • make sure staff (and students where appropriate) are properly informed about and trained to control or deal with the risks from the dangerous substances;
  • identify and classify areas of the workplace where explosive atmospheres may occur and avoid ignition sources (from unprotected equipment, for example) in those areas.

All actions, including DSEAR risk assessments, must comply under the DSEAR Approved Code of Practice and Guidance (ACOP 2nd Edition 2013).

Examples of DSEAR

Examples of activities covered by DSEAR include:

  • storage of petrol as a fuel for cars, boats or horticultural machinery;
  • use of flammable gases, such as acetylene, for welding;
  • handling and storage of waste dusts in a range of manufacturing industries;
  • handling and storage of flammable wastes such as fuel oils;
  • welding or other ‘hot work’ on tanks and drums that have contained flammable material;
  • work that could release naturally occurring flammable substances such as methane in coalmines or at landfill sites;
  • use of flammable solvents in laboratories;
  • storage and display of flammable goods, such as paints, in shops;
  • filling, storing and handling aerosols with flammable propellants such as LPG;
  • transporting flammable substances in containers around a workplace;
  • deliveries from road tankers, such as petrol and bulk powders;
  • chemical manufacturing, processing and warehousing;
  • the petrochemical industry, both onshore and offshore;
  • handling, storage and use of gases under pressure;
  • handling, storage and use of substances corrosive to metal.

Possible Control Measures

Where the risk cannot be eliminated, DSEAR requires control measures to be applied in the following priority order:

  • reduce the quantity of dangerous substances to a minimum;
  • avoid or minimise releases of dangerous substances;
  • control releases of dangerous substances at source;
  • prevent the formation of a dangerous atmosphere;
  • collect, contain and remove any releases to a safe place (for example, through ventilation);
  • avoid ignition sources;
  • avoid adverse conditions (for example, exceeding the limits of temperature or control settings) that could lead to danger;
  • keep incompatible substances apart.