The Control of Substances Hazardous to Health Regulations 2002, known everywhere as COSHH, are the main UK rules for protecting people from harm caused by chemicals, dusts, fumes and other hazardous substances at work. They apply to almost every workplace, from a warehouse with a shelf of cleaning products to a factory running solvents and coolants. This guide explains what COSHH covers, what employers must do under regulations 6 to 13, and where storage fits in, so you can tell what the law requires from what is simply good practice.
What are the COSHH Regulations 2002?
The Control of Substances Hazardous to Health Regulations 2002 (SI 2002/2677, as amended) are made under the Health and Safety at Work etc. Act 1974. They require employers to prevent or adequately control exposure to substances that can harm health. The Health and Safety Executive publishes the Approved Code of Practice and guidance in L5, Control of substances hazardous to health, which is the best plain-English reference for what “adequate” means in practice.
The duties are owed to employees and also, so far as reasonably practicable, to other people who may be affected by your work, such as contractors and visitors. COSHH sits alongside the Management of Health and Safety at Work Regulations 1999, which set the general duty to assess risk.
What counts as a substance hazardous to health?
HSE describes hazardous substances as including chemicals, fumes, dusts, vapours, mists, gases and biological agents. As a rule of thumb, if the packaging carries a hazard pictogram it is classed as hazardous to health, and the supplier must provide a safety data sheet for it. Everyday examples in a UK workplace include:
- Cleaning products, bleach, degreasers and descalers.
- Paints, adhesives, solvents, thinners and resins.
- Oils, fuels, coolants, welding fume and wood or cement dust.
- Agrochemicals, acids and alkalis.
- Biological agents, such as bacteria in a cooling system or waste-handling environment.
Some hazards are handled by other regulations. Lead and asbestos have their own dedicated regulations, and substances that are dangerous only because they are flammable or explosive fall under the Dangerous Substances and Explosive Atmospheres Regulations rather than COSHH. Our guide to DSEAR explains where that line falls.
What employers must do: regulations 6 to 13
Most of the practical duties sit in regulations 6 to 13. In short:
- Regulation 6, risk assessment. You must not carry out work that could expose people to a hazardous substance until you have made a suitable and sufficient assessment of the risk and the steps needed to comply. If you employ five or more people, the significant findings must be recorded under the Management of Health and Safety at Work Regulations 1999.
- Regulation 7, prevent or control exposure. Prevention comes first, for example by removing the substance or substituting a safer one. Where that is not reasonably practicable, exposure must be adequately controlled. Personal protective equipment is the last resort, not the first, and it needs to be chosen and managed properly; see our guide to the PPE at Work Regulations 1992.
- Regulation 8, use of control measures. Employers must make sure control measures are actually used, and employees must use them and report defects.
- Regulation 9, maintenance, examination and testing. Control measures must be kept in efficient working order. Local exhaust ventilation has to be thoroughly examined and tested at least once every 14 months, with records kept.
- Regulation 10, monitoring exposure. Where it is needed to make sure exposure limits are not exceeded or controls are working, you must monitor exposure. Workplace exposure limits are published in HSE’s EH40/2005.
- Regulation 11, health surveillance. Where there is an identifiable disease or adverse health effect linked to the exposure, employees must be under suitable health surveillance, and health records are kept for at least 40 years.
- Regulation 12, information, instruction and training. Anyone who may be exposed must know the risks, the results of any monitoring and the precautions they should take.
- Regulation 13, accidents, incidents and emergencies. You need procedures, first-aid provision and safety drills for the foreseeable spills and releases, and the people who deal with them need to be trained.
How to carry out a COSHH risk assessment
There is no single mandatory format, but a sensible assessment follows a clear sequence. It is worth working through it in order:
- List what you use. Walk the site and record every hazardous product, where it is kept, how much, and who handles it. Many businesses keep this as a COSHH register or inventory. No regulation calls it that, but you cannot assess what you have not listed.
- Read the safety data sheet. Suppliers must provide one for hazardous products. Section 7 covers handling and storage, section 8 exposure controls and personal protection, and section 10 stability and reactivity, which tells you what the product must be kept away from.
- Decide who could be harmed and how. Think about breathing, skin contact, eye contact, swallowing and injection, and about cleaners, maintenance staff, agency workers and visitors as well as the regular operators.
- Remove or substitute where you can, then decide what control is adequate for what remains: ventilation, enclosure, safer handling methods, limiting time and numbers exposed.
- Record, communicate and train. Tell people what you found and what they must do, and make sure the controls are in use.
- Review. Reassess if the process, the substance or the quantities change, or if health surveillance or monitoring suggests the controls are not working.
What goes in a COSHH assessment?
A COSHH assessment is the written record of your risk assessment for a hazardous substance or process. HSE does not mandate one format, but a useful COSHH assessment normally records:
- The substance or process, where it is used and stored, and the quantities involved.
- The hazards, taken from the label and the safety data sheet.
- Who could be exposed and by which route: breathing it in, skin or eye contact, swallowing or injection.
- The controls in place, such as ventilation, safer handling, limiting numbers exposed, storage and PPE.
- What to do in a spill, release or first-aid situation.
- Who carried out the assessment, the date, and when it will be reviewed.
If you employ five or more people, you must record the significant findings. Below that number the assessment still has to be done, but the written record is not a legal requirement, although many employers keep one anyway.
COSHH assessment or safety data sheet?
They are not the same thing. The safety data sheet comes from the supplier and describes the product in general. The COSHH assessment is yours: it looks at how you actually use the product, in what quantity, by whom and with what controls. The safety data sheet is an input to the assessment, not a substitute for it.
COSHH and storage: what the law does and does not say
This is where a lot of confusion arises. COSHH does not contain a rule saying that every hazardous product must live in a “COSHH cabinet”, and the cupboard does not have to be any particular colour. What it does require is that exposure is prevented or adequately controlled, and how you store a substance is part of that. In practice, sensible storage means:
- Keeping only the quantity you need in the work area, with bulk stock in a designated store.
- Keeping incompatible substances apart, for example acids away from alkalis and oxidisers away from fuels, following section 10 of each safety data sheet.
- Using containers that suit the substance and are properly labelled, never decanting into unlabelled or food and drink containers.
- Providing secondary containment, such as an integral sump or a bund, so that a leak stays where it can be dealt with. For larger volumes see our guide to spill containment and bunding.
- Restricting access to people who have been trained, which is where lockable storage helps.
If your risk assessment concludes that lockable, sumped storage is the right control, a purpose-built cabinet is a straightforward way to deliver it. Our COSHH cabinet requirements guide covers what to look for, COSHH cabinet sizes and capacities helps with choosing one, and flammable cabinet versus COSHH cabinet explains why the two are not interchangeable. If the substance is a flammable liquid, read how flammable liquids should be stored as well.
You can browse the range at COSHH cabinets, or see the wider hazardous storage range. For bulk liquids there are drum sump pallets and IBC bunds, and the full spill containment range. Always check any product against the safety data sheet for what you actually store before you buy.
Labels, symbols and safety data sheets
Hazardous products are labelled under the CLP Regulations with pictograms, signal words and hazard statements. Knowing what the diamonds mean is part of the information and training duty in regulation 12. Our guide to COSHH symbols and their meanings walks through each one. Keep safety data sheets where the people using the product can reach them, and keep them current: an out-of-date sheet is a weak foundation for an assessment.
Common COSHH mistakes
- Writing one generic assessment for the whole site instead of assessing the actual tasks, quantities and people involved.
- Reaching for PPE first, rather than removing or reducing the hazard.
- Forgetting cleaners, maintenance staff, contractors and agency workers when working out who is exposed.
- Storing incompatible products together because the shelf was convenient.
- Letting the inventory and safety data sheets go out of date when products change.
- Assuming a cabinet on its own makes a workplace compliant. It is one control among several.
Where to find the official guidance
The regulations are on legislation.gov.uk as SI 2002/2677, and HSE’s L5 and the COSHH pages on hse.gov.uk explain them in detail, including the free COSHH assessment guidance. For a specific process, substance or exposure, take advice from a competent health and safety adviser or occupational hygienist. This guide is general information for UK workplaces and is not legal advice.