Short answer. DSEAR is the Dangerous Substances and Explosive Atmospheres Regulations 2002. It applies to every workplace in Great Britain where a substance that could burn or explode is present, from the diesel tank in a yard to the flour in a bakery, and it requires the employer to assess the risk, control it, classify any area where an explosive atmosphere could form, and be ready for an emergency. It is a separate duty from the fire risk assessment and from COSHH.
Working out which of your substances and processes fall under it is a DSEAR assessment, which York Green carries out on site.
What does DSEAR stand for?
Dangerous Substances and Explosive Atmospheres Regulations. The regulations came into force in 2002, were made under the Health and Safety at Work etc. Act 1974, and brought two European directives into British law: one on explosive atmospheres at work, one on chemical agents. They are usually said as a word, "dee-sear". The HSE's Approved Code of Practice, L138, explains how to comply.
What are the DSEAR regulations?
There are seventeen regulations, and seven of them are the ones an employer deals with day to day. Regulation 5 requires a risk assessment of the dangerous substances present. Regulation 6 requires the risk to be eliminated or reduced, following a set order: substitute the substance, reduce the quantity, avoid releases, control releases at source, keep ignition sources away, and then mitigate what is left. Regulation 7 requires places where an explosive atmosphere could form to be classified into zones and marked. Regulation 8 requires arrangements for accidents, incidents and emergencies. Regulation 9 requires information, instruction and training for employees. Regulations 10 and 11 cover identification of containers and pipes, and the duty of coordination where more than one employer shares a workplace.
What counts as a dangerous substance under DSEAR?
Anything that could create a fire or an explosion because of its properties or the way it is used. In practice that means flammable liquids (petrol, diesel, solvents, paints, thinners, alcohol), flammable gases (natural gas, LPG, hydrogen, acetylene), combustible dusts (flour, sugar, wood, grain, powder coatings, some metals), and substances that react dangerously, such as oxidisers. The quantity matters less than people expect. A few litres of solvent in a badly ventilated cupboard can form an explosive atmosphere.
Which workplaces does DSEAR apply to?
Any workplace with a dangerous substance present, whatever the trade. The obvious ones are chemical plants, paint shops, fuel storage and anything with a hazardous area drawing already on the wall. The ones that get missed are everywhere else: the boiler room and gas pipework in an office block, the forklift charging bay in a warehouse, the flour store in a bakery, the woodworking shop, the garage with a petrol-engined fleet, the brewery, the lab, the farm with a diesel tank, the school with a science prep room. If the answer to "is there anything here that could burn or explode" is yes, DSEAR applies.
Is DSEAR a legal requirement?
Yes. It is a statutory duty on the employer, and the self-employed are treated as employers under the regulations. There is no exemption for small businesses and no threshold quantity below which the regulations do not apply. The requirement is proportionate, so a single bottled-gas heater needs a short assessment and a solvent store needs a longer one, but the duty to assess is the same.
Do I need a DSEAR assessment?
If your general risk assessment or your fire risk assessment has identified a dangerous substance, yes. The fire risk assessment looks at the building and the people in it; the DSEAR assessment looks at the substance, the process and the explosive atmosphere, and it goes into the detail the fire assessment does not: how much is released, how far it spreads, how long it lingers, what could ignite it, and which zone that makes the area. A fire risk assessor will often flag that a DSEAR assessment is needed rather than carry one out.
When is a DSEAR assessment required?
Before the work starts, in law, and in practice as soon as the substance arrives. It also has to be revisited when the substance, the quantity, the process, the equipment or the building changes, after any incident or near miss, and when the control measures are found not to work. A new extraction system, a new product line, a change of supplier or a move to a new unit all trigger a review.
Who can carry out a DSEAR risk assessment?
Someone competent: with the training, knowledge and experience to understand the substances, the processes and the way explosive atmospheres form, and to classify zones correctly. There is no single qualification required by law. In practice it means a health and safety or process safety professional who knows DSEAR, ATEX and the relevant British Standards, and who can show comparable work. The employer stays responsible for the assessment being suitable and sufficient, so it is worth asking to see the evidence.
How often should a DSEAR assessment be carried out?
The regulations set no fixed interval. The assessment stays valid until something changes, so the real answer is: review it when the substance, process, equipment or building changes, after any incident, and otherwise at a sensible interval set by the risk. For most sites an annual review with a full reassessment when the process changes is the pattern that works.
How much does a DSEAR risk assessment cost?
It depends on the number of substances, the number of locations, the complexity of the process and whether zone classification and drawings are needed. A boiler room is at the bottom of the range; a multi-process site with dust and flammable liquids is at the top. York Green publishes its range and fixes the price in writing after the Greenlight Call: see the DSEAR assessment page.
DSEAR and ATEX: what is the difference?
ATEX is the name given to two European directives. One covers the equipment used in explosive atmospheres (the "Ex" marking on a motor or a light fitting) and is a product standard that your suppliers have to meet; in Britain it is enforced through separate equipment regulations. The other covers the workplace, and that is the one DSEAR brought into British law. So when someone asks for "an ATEX assessment" of a site, what they need is a DSEAR assessment. The full comparison is in DSEAR vs ATEX.
DSEAR and COSHH: what is the difference?
COSHH is about substances that harm health: toxic, corrosive, sensitising. DSEAR is about substances that burn or explode. Many substances are both (a solvent can poison you and ignite), so both assessments apply and they are best done together. The split is explained in COSHH vs DSEAR.