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DSEAR Regulations

We are often asked by businesses “what are dangerous substances?” and “does our business need to undertake a DSEAR assessment?”. The HSE website provides an excellent starting point for any business to help identify in detail what all businesses need to know. The HSE identifies that dangerous substances are any substances used or present at work that could, if not properly controlled, cause harm to people as a result of a fire or explosion.

In practical terms they can be found in nearly all workplaces and include such things as solvents, flammable paints, varnishes, flammable gases (such as LPG and Acetylene), and dusts that can be created as a by-product (e.g. from sanding, or in waste handling), or dusts from foodstuffs.

What does DSEAR require?

As a business you first need to know what substances in your workplace have the potential to present fire and explosion risk. We find that too many businesses fail to understand this and are therefore putting their employees and business at risk.

It’s only when the above is properly identified that your business can think about making sure the risks are properly controlled; either by removing the risk or through risk reduction. Another problem is that businesses fail to consider all of their processes; as many DSEAR risks are often associated to maintenance and cleaning. Therefore it is imperative that your business considers what controls would be needed for these activities. For example, are Permits to Work required?

Because of the nature of hazardous substances it is also imperative to consider what would happen if something was to go wrong and to have in place emergency planning. It may even be necessary to inform the local Fire Service of these plans; it’s a key recommendation that we make to clients with flammable gases (especially Acetylene).

Another important action is to make sure employees are properly informed about and trained to control or deal with the risks from the dangerous substances. It’s an area that far too many businesses fail to deal with properly and we are amazed at how little training employees usually have and how this lack of awareness increases the potential risks on their safety and the safety of the business.

A fundamental requirement of DSEAR is to identify and classify areas of the workplace where explosive atmospheres may occur. Where explosive atmospheres may occur these must be classified into hazardous zones based on the risk of an explosion occurring, and protected from sources of ignition by selecting suitable equipment and protective systems.

So what is ATEX and explosive atmospheres?

Explosive atmospheres can be caused by flammable gases, mists or vapours or by combustible dusts. If there is enough of the substance, mixed with air, then all it needs is a source of ignition to cause an explosion.

Explosions can cause loss of life and serious injuries as well as significant damage. Preventing releases of dangerous substances, which can create explosive atmospheres, and preventing sources of ignition, are two widely used ways of reducing the risk. Using the correct equipment can help greatly in this.

Many workplaces may contain, or have activities that produce, explosive or potentially explosive atmospheres. Examples include places where work activities create or release flammable gases or vapours, such as vehicle paint spraying, or in workplaces that undertake welding; or where handling fine organic dusts such as grain, flour or wood.

ATEX is a European directive and in Great Britain the requirements of Directive 99/92/EC were put into effect through regulations 7 and 11 of the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR).

What does your business need to do?

DSEAR requires employers to eliminate or control the risks from dangerous substances – further information on these requirements can be found at

In addition to the general requirements, the regulations place the following specific duties on employers with workplaces where explosive atmospheres may occur …

Classification of areas where explosive atmospheres may occur

Employers must classify (into zones) areas where hazardous explosive atmospheres may occur. The classification given to a particular zone, and its size and location, depends on the likelihood of an explosive atmosphere occurring and its persistence if it does. It is important to understand these requirements fully, as failure could lead to:

  1. An area going unclassified and leading to ignition of a flammable atmosphere; or
  2. Over rating of a hazardous zone; this can make operating in such zones very expensive and sometimes incurring unnecessary expenditure.

By accessing the BSI standards you can find detailed information and guidance on the classification and zoning of areas where potentially explosive atmospheres may occur and the selection of equipment for use in those areas.

Selection of equipment and protective systems

Areas classified into zones must be protected from sources of ignition. Equipment and protective systems intended to be used in zoned areas should be selected to meet the requirements of the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 1996. Equipment already in use before July 2003 can continue to be used indefinitely provided a risk assessment shows it is safe to do so.

Where necessary, the entry points to areas classified into zones must be marked with a specified ‘EX’ sign.

Static is a potential source of ignition that is often not properly considered; we have helped a some businesses who, to their cost, had not recognised the risks and unfortunately found out the hard way. Making sure that you have suitable earthing controls can help prevent fires and explosions. Additionally, providing anti-static clothing may be necessary – depending upon the level of risk identified in the risk assessment. Employees may need to be provided with suitable clothing and footwear if working in zoned areas.

Confirming (verifying) overall explosion safety

Before a workplace containing zoned areas comes into operation for the first time, the employer must ensure that the overall explosion safety measures are confirmed (verified) as being safe. This must be done by a person or organisation competent to consider the particular risks in the workplace, and the adequacy of the explosion control and other measures put in place.

It may be possible in some instances to do this from within your organisation but a word of caution; think very carefully about whether you have the necessary competence in your business.

Further assistance

It may be useful for you to see some examples of DSEAR risk assessments we’ve undertaken within specific industry sectors, which may help you to understand how the DSEAR regulations may apply to your particular business.

It may also be useful for you to see an example of a completed DSEAR risk assessment or to see our DSEAR risk assessment template.

If you would like some initial free advice on how the DSEAR regulations may relate to your individual business, please do contact us and we’ll be happy to help you.