6th December 2016


 Issue No.  2016/24




Or to give it it’s full title...

The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR)
DSEAR sets minimum requirements for the protection of workers from fire and explosion risks related to dangerous substances and potentially explosive atmospheres and from gases under pressure and substances corrosive to metals.  They require employers to control the risks to the safety of employees and others arising from these hazards.

Materials that are capable of forming flammable or explosive atmospheres are classed as dangerous substances and are defined in the Regulations.

What is an Explosive Atmosphere?
An explosive atmosphere is a mixture of a dangerous substance or substances (gas, mist, dust or vapour) within air, which has the potential to catch fire or explode.  An explosive atmosphere does not always result in an explosion but, if it does catch fire, the flames travel quickly.  If this happens in a confined space (e.g. in plant and equipment or production premises), the rapid spread of flames or rise in pressure could also cause an explosion.

Where can they occur?
Explosive atmospheres can be formed in workplaces where dangerous substances (such as flammable and explosive materials) are manufactured, stored, moved, used or transported and where dusts are formed.  In practice this means factories, warehouses, store rooms, plant and equipment, moveable structures, outdoor areas and even domestic premises (this is not an exhaustive list).  

When Does DSEAR Apply?
The DSEAR Regulations apply to the majority of work activities where: 

  • Work is being carried out by an employer (or self-employed person);
  • A dangerous substance is present (or is liable to be present or generated) at the workplace;
  • A potentially explosive atmosphere may occur; and
  • The dangerous substance and / or potentially explosive atmosphere could be a risk to the safety of people as a result of fires, explosions or similar energetic events or through corrosion to metal

Dangerous Substances are defined in DSEAR as substances or preparations that are: 


Flammable, highly flammable or extremely flammable



Compressed gases

 Examples of labelled dangerous substances include:

  • Petrol
  • flammable gases
  • liquefied petroleum gas (LPG)
  • various solvents and solvent-based paints
  • varnishes
  • peroxides
  • dust that can form an explosive mixture with air e.g. grain dust, flour, sugar, wood dust, cotton dusts, oxides of aluminium
  • materials produced in the workplace, even transiently, that create a comparable risk e.g. methane from the decomposition or organic waste, by-products from chemical reactions.

Does DSEAR Affect You?
A substantial list of activities and sectors (too big to reproduce here) is available here.

Employers DSEAR Duties
Under DSEAR employers must:

  • Ensure, as far as is reasonably practicable, the health and safety at work of employees where explosive atmospheres maybe present;
  • Carry out Risk Assessments on areas where explosive atmospheres could occur;
  • Eliminate or reduce the risks, as far as is reasonably practicable, by the introduction of control measures;
  • Classify areas where explosive atmospheres could occur;
  • Mark points of entry;
  • Have procedures to collect, contain and remove any releases to a safe place e.g. using ventilation;
  • Have accident and emergency procedures and the required equipment to deal with an explosion incident;
  • Give employees (and relevant others) suitable and sufficient information, instruction and training on the risks and measures in place;
  • Provide employees with suitable PPE such as anti-static clothing;
  • Provide and ensure the proper use of equipment designed only for explosive atmospheres.
  • Make arrangements to protect employees from an accident, incident or emergency.
  • Prevent sources of ignition.
  • Ensure that the contents of pipes and containers containing dangerous substances are clearly identified.

If you need help in any of the issues raised here please do not hesitate to contact us. 





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