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What Counts as a Hazardous Substance Under COSHH?
“Hazardous substance” sounds like it means industrial chemicals in a lab somewhere — in reality, the scope of COSHH is far broader, and covers things most workplaces use every single day without thinking twice.
The short version
- COSHH covers substances that are hazardous to health, not just substances that are dangerous in an obvious, dramatic sense.
- This includes cleaning products, fumes, dusts, gases, vapours, and biological agents like bacteria encountered through certain work.
- If a product carries a hazard warning symbol on its label, it almost certainly falls under COSHH.
The main categories
- Chemical products — cleaning agents, disinfectants, sanitisers, degreasers, and any product carrying a hazard warning label (corrosive, irritant, toxic, flammable).
- Fumes and vapours — from cooking (particularly deep-frying and char-grilling), cleaning products, or equipment.
- Dusts — flour dust in a bakery is a genuine, well-documented COSHH consideration, alongside more obvious construction or industrial dusts.
- Gases — including carbon monoxide risk from poorly maintained gas equipment.
- Biological agents — bacteria, viruses or moulds that workers could be exposed to through certain work, including some food handling and waste management tasks.
Why the scope catches people off guard
Most people picture COSHH as being about obviously dangerous industrial chemicals, and are surprised to learn that the everyday cleaning products used in almost every kitchen, care home or office fall squarely within it. If a product’s label carries any hazard pictogram — even a common one for irritants — it’s a COSHH substance, and needs to be assessed, stored, used and disposed of according to COSHH principles.
What COSHH actually requires you to do about it
For any hazardous substance genuinely present in your workplace, the Control of Substances Hazardous to Health Regulations 2002 require you to assess the risk, put in place adequate control measures (proper storage, ventilation, protective equipment), and provide staff with the information, instruction and training needed to work with it safely.
A practical example: kitchen cleaning chemicals
A typical commercial kitchen might use an oven cleaner, a sanitiser and a descaler — all three are likely to carry hazard warnings, meaning all three fall under COSHH. That means safe storage away from food, proper dilution and use according to the manufacturer’s instructions, and staff trained to handle them correctly rather than just “knowing where the spray bottle is.”
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Frequently asked questions
Does flour count as a hazardous substance under COSHH?
Yes — flour dust is a recognised COSHH consideration, particularly in bakeries and high-volume kitchens, due to the respiratory risks of prolonged dust exposure.
How do I know if a product I use falls under COSHH?
Check the label for hazard warning symbols, and check the product’s safety data sheet (SDS), which the supplier is legally required to provide — if either indicates a health hazard, it falls under COSHH.
Does COSHH cover physical hazards like sharp knives or hot surfaces?
No — COSHH is specifically about substances hazardous to health. Physical hazards like knives, hot equipment or slips are covered under general workplace health & safety, a separate area of law.