Dangerous Substances and Explosive Atmospheres Regulations UK 20021

These set the minimum requirements for the protection of workers from fire and explosion risks related to dangerous substances and potentially explosive atmospheres and require the employers to control those risks and protect their workforce.
This includes the following to be carried out and documented to establish what dangerous substances are used and associated risks in relation to ‘Hazardous areas:

  • Site Risk Assessments for explosive gases and vapours
  • Physical characteristics of the hazard
  • Hazardous area classifications (Zones)
  • Permit to work procedures
  • Assessment of all electrical and non-electrical equipment
  • Electrical equipment and installations are documented inspected and maintained
  • procedures and equipment are available to deal with incidents
  • Information and training are provided for employees

If the hazard, gas or vapour, is unknown e.g. undefined vapours from a liquid then the requirements of DSEAR are clear that the source should be analysed to assess relevant gas parameters e.g Gas group, T Class, density.
Based on that information it is not unreasonable to make some assumptions2 as long as justification is given.

Note the As they were published in 2002 the DSEAR Regulation quotes the 94/9/EC Atex Directive and The Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 1996 rather than Atex 2014/34/EU Directive and the 2016 regulation which brought in significant changes to the legal standing of Hazardous Area assessments particularly relating to Competency and Liability.

On Brexit, the Product Safety and Metrology etc. (Amendment etc.) (EU Exit) Regulations 2019 again amended the wording of DSEAR 2002.

The DSEAR assessment must be carried out by a ‘Competent’ person, either within the company or more common via a consultancy.
Whoever is carrying out the DSEAR assessment must be able to demonstrate an understanding, training or experience, of Hazardous areas and the relevant EN 60079 standards and preferably the application i.e. an understanding of the assesed business or similar.

Hazardous area assessment is a specialised area of DSEAR, prior to taking advice from a consultant evidence of ‘Competency’ should be obtained. There are a few consultancies who don't even reference the current regulations and standard, (on web site & documents) suggesting they rely solely on the DSEAR guidelines rather than the relevant Regulation/Standards. All current standards and guidelines reference at least the 2014 Directive and 2016 Regulations which would suggest, at best, those consultancies are not up to date or looked at current standards and certainly Competency should be questioned

For more information on the the DSEAR assessement please refer to Zones and Gas Groups


  1. Implemented in Northern Ireland 2003 

  2. Any assumptions should be detailed in the DSEAR Report, rather then presenting them as facts.