DSEAR stands for the Dangerous Substances and Explosive Atmospheres Regulations 2002. They apply wherever a dangerous substance is, or is liable to be, present at a workplace, and they are about fire, explosion and similar energetic events rather than about long-term ill health, which is COSHH's territory. A garage, a paint shop, a bakery with flour dust, a distillery and a farm with a diesel store are all in scope.
What the DSEAR regulations require
Regulation 5 requires a suitable and sufficient assessment of the risks arising from a dangerous substance, considering the substance's hazardous properties, the supplier's safety information including any safety data sheet, the circumstances of the work, the likelihood that an explosive atmosphere will occur and persist, the likelihood of ignition sources being present and becoming active, and the scale of the anticipated effects.
Duty holders, and what they have to do about it
Eliminate the risk where possible by substituting a substance or a process, and where that is not possible control it and mitigate the effects. That means controlling releases, avoiding ignition sources, segregating incompatible substances, providing explosion relief or suppression where appropriate, and preparing emergency arrangements. Hazardous areas have to be classified into zones and marked, and equipment used in them has to be suitable for the zone.
How DSEAR and ATEX fit together
ATEX is the equipment and protective systems side: the standards and conformity requirements for kit intended for use in potentially explosive atmospheres. DSEAR is the duty on the employer to assess, classify and control. In practice the DSEAR assessment tells you the zone, and the zone tells you what ATEX category of equipment is acceptable in it. Buying ATEX-rated equipment without a DSEAR assessment is buying an answer to a question nobody has asked.
Where businesses get caught out
Small quantities. Duty holders assume DSEAR is for refineries, and then discover it applies to the cellar with the carbon dioxide cylinders, the workshop with the oxy-acetylene set, and the woodworking shop whose extraction system moves fine dust. The trigger is that a dangerous substance is present, not that the site is industrial.
Questions people ask about DSEAR assessment
What does DSEAR stand for?
The Dangerous Substances and Explosive Atmospheres Regulations 2002.
What does DSEAR require duty holders to do?
Assess the risk from dangerous substances under regulation 5, eliminate or reduce it, classify and mark hazardous areas into zones, control ignition sources, and prepare emergency arrangements.
What is the difference between DSEAR and COSHH?
DSEAR is about fire, explosion and corrosion to metals from dangerous substances. COSHH is about harm to health from exposure. Many substances engage both, and they need separate assessments.
Does a small workshop need a DSEAR risk assessment?
If a dangerous substance is or is liable to be present, yes. Quantity affects the scale of the controls, not whether the duty applies.
What is the dsear meaning, and what does it cover?
Dangerous Substances and Explosive Atmospheres Regulations, and what they cover is fire and explosion rather than health. That is the line between them and COSHH: the same solvent can be a COSHH substance because of what it does to a person's lungs and a dangerous substance because of what its vapour does near an ignition source, and both assessments can be owed on one drum. The scope is wider than it sounds. Petrol and solvents, yes, but also flammable dusts from timber, flour and metal, gases in cylinders, and oxygen enrichment, which makes ordinary materials burn in ways nobody expects.
What is a DSEAR risk assessment, and is it separate from the general one?
It is the same duty applied to one family of hazards, and it is usually written as its own document because the questions are specific: which dangerous substances are present and in what quantity, where an explosive atmosphere could form and how often, what could ignite it, and what the consequences would be. The findings then feed the general assessment rather than replacing it. Keeping it separate is practical rather than legal, because the zoning drawings, the substance inventory and the ignition source survey are what an inspector and an insurer both ask to see, and burying them inside a general assessment makes them impossible to review.