DSEAR Regulations

The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) are concerned with preventing or limiting the harmful effects of fires, explosions and similar energy-releasing events and corrosion to metals. DSEAR are goal-setting regulations and are supported by an  Approved Codes of Practice (ACOP) that provides practical advice on how to comply with them.


The Dangerous Substances and Explosive Atmospheres Regulations 2002 are concerned with protection against risks from fire, explosion and similar events arising from dangerous substances used or present in the workplace. From June 2015 DSEAR also covers gases under pressure and substances that are corrosive to metals. This is to allow for changes in the EU Chemical Agents Directive the physical hazards aspects of which are enacted in Great Britain through DSEAR.

They set 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 and require employers to control the risks to the safety of employees and others from these hazards.

Further information:

ATEX and explosive atmospheres

Explosive atmospheres in the workplace can be caused by flammable gases, mists or vapours or by combustible dusts. Explosions can cause loss of life and serious injuries as well as significant damage.

DSEAR require that any workplace where explosive atmospheres may occur are classified into hazardous zones based on the risk of an explosion occurring, and protected from sources of ignition by selecting equipment and protective systems on the basis of the categories set out in the Equipment and Protective Systems for Use in Potentially Explosive Atmospheres Regulations (EPS)

Further information:


Petrol is a dangerous substance and is a highly flammable liquid which can give off flammable vapour, even at very low temperatures. This means there is always a risk of fire and explosion when a source of ignition is present and when ignited it can quickly cause fire, injury and loss of life. Storing and dispensing petrol at a workplace is covered by the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR), and other legislation specifically for controlling petrol storage and the suitable containers for storing petrol in.

Further information:

Work process fire safety

There are thousands of recorded fires in commercial premises every year. HSE's main responsibility in this area is for the special precautions within a work process which are designed to prevent or reduce the likelihood of a fire breaking out or (should a fire break out) reduce its intensity. HSE also has enforcement responsibility for process fire safety on construction sites, for nuclear premises and on ships under construction or repair.

These pages provide information about HSE's role:

Gases under pressure and substances corrosive to metals

Gases that are under pressure (eg gas in a cylinder) may present a risk of explosion if not correctly handled in the workplace. Substances that can corrode metals could cause structural damage reducing integrity of structures if not suitably contained. From June 2015, DSEAR places a formal requirement on employers to assess the risks for substances if classified for these properties and put in place suitable control and mitigation measures. It is anticipated that the practical impact, if any, of these changes will be minimal because the intrinsic hazards of the substances being used, or present, in workplaces is unchanged. The need to carry out a risk assessment and have in place procedures for the safe use of chemicals not currently covered by DSEAR is already required by the general requirements of the Health and Safety at Work etc Act 1974 and the Management of Health and Safety at Work Regulations 1999. Therefore, assuming businesses are already complying with these duties, they are unlikely to need to take any additional action.


Private individuals and voluntary groups may come into contact with old film in their home or at other non-workplace premises. Old cinematographic film and old photographic negatives (including X-ray film) may be made from cellulose nitrate.

Cellulose nitrate film can be very dangerous; it catches fire easily and once alight is difficult to put out.

The free HSE leaflet 'The dangers of cellulose nitrate film' gives more information.

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Updated 2020-12-08