The diamond-shaped red-bordered symbols on a container are hazard pictograms under the chemical classification and labelling regime, and everyone calls them COSHH symbols because COSHH is where they meet them. There are nine of them in Great Britain. They tell you a class of hazard is present, which is genuinely useful at a glance and much less than an assessment needs. This page lists them, says what each is telling you, and is clear about the gap between recognising a symbol and controlling an exposure.
The nine, and what each one is signalling
Explosive, for substances and mixtures that can explode. Flammable, for those that catch fire easily. Oxidising, for those that intensify a fire in other materials. Corrosive, for those that damage skin, eyes or metal. Acute toxicity, the skull and crossbones, for those that are poisonous at low doses. Hazardous to the environment, for those that harm aquatic life. The exclamation mark, for health hazards including irritation and, in Great Britain, the ozone layer. The serious health hazard figure, for effects such as carcinogenicity, respiratory sensitisation and reproductive toxicity. And gas under pressure, for compressed, liquefied and dissolved gases.
They are labelling symbols, not COSHH symbols
The distinction matters more than it sounds. The pictograms come from the classification and labelling rules that suppliers must follow when placing a substance on the market. COSHH is the separate duty on the employer to assess and control exposure at work. A container with no pictogram may still need assessing, because process-generated dust and fume arrive with no label at all, and a container with a pictogram tells you a class of hazard rather than what your people are actually exposed to.
What a pictogram cannot tell you
How much of it your people breathe in an hour. Whether your extraction is working. Whether the substitute you could use instead is available. Whether a sensitiser has already sensitised somebody, which is the sort of thing health surveillance exists to catch. The symbol is the start of the enquiry. Firms that build their safety programme on recognising symbols end up with well-labelled stores and unassessed processes.
Signs and labels around the store are a control, and they are the smallest one
Decanted containers must be labelled, storage areas signed, and incompatible substances separated, and all of that is worth doing. It is also the cheapest and least effective layer of the hierarchy, and it is where firms concentrate because it is visible. The order that reduces harm is elimination, substitution, engineering control, ways of working, then equipment and signage; the free COSHH assessment worksheet on this site prices the assessing that decides which of those you actually need.
Questions people ask about coshh symbols and meanings
How many COSHH symbols are there?
Nine hazard pictograms are listed under the GB classification and labelling regime: explosive, flammable, oxidising, corrosive, acute toxicity, hazardous to the environment, the exclamation mark health hazard, the serious health hazard, and gas under pressure. They are properly called hazard pictograms rather than COSHH symbols.
What do the COSHH signs and labels in a store have to show?
Containers should keep their supplier label, and anything decanted needs labelling with the same hazard information; storage areas are signed and incompatible substances kept apart. None of that replaces the assessment, and a store that is beautifully labelled while the process next to it is unassessed is a common and unhelpful pattern.
Did the pictograms replace the old orange symbols?
The current GB regime uses the red-bordered diamond pictograms listed above. Older orange square symbols still turn up on legacy stock and in old training material, and a container carrying them is worth a look at its date and its sheet, because an out-of-date classification is a reason to reassess rather than a curiosity.