COSHH Symbol Meanings
What do the COSHH symbols mean?
"COSHH symbols" are the nine hazard pictograms that go on chemical labels under the GB CLP Regulation. Each is a black symbol on a white diamond with a red border, and each stands for a fixed group of hazard classes (HSE). COSHH doesn't create the symbols itself. HSE's COSHH guidance tells employers to start their risk assessment by checking whether any product has a danger label with these symbols and reading its safety data sheet (HSE INDG136, p.3).
Approach: I used HSE's pictogram and COSHH guidance and Annex V of the CLP Regulation on legislation.gov.uk. The hazard classes below come from Annex V. HSE's own pages give only the symbol names. The regional datasets I can search hold GB classification lists but not this pictogram guidance.
| Symbol (code) | HSE name | What it covers (CLP Annex V) |
|---|---|---|
| Exploding bomb (GHS01) | Explosive | Unstable explosives; explosives Divisions 1.1–1.4; self-reactive substances and organic peroxides Types A–B |
| Flame (GHS02) | Flammable | Flammable gases (1A, 1B), aerosols, liquids and solids; pyrophoric and self-heating substances; substances that give off flammable gas in contact with water; self-reactives and organic peroxides Types B–F; desensitised explosives |
| Flame over circle (GHS03) | Oxidising | Oxidising gases, liquids and solids |
| Gas cylinder (GHS04) | Gas under pressure | Compressed, liquefied, refrigerated liquefied or dissolved gases |
| Corrosion (GHS05) | Corrosive | Corrosive to metals; skin corrosion (Cat. 1, 1A–1C); serious eye damage (Cat. 1) |
| Skull and crossbones (GHS06) | Acute toxicity | Acute toxicity (oral, dermal or inhalation), Categories 1–3, the most severe |
| Exclamation mark (GHS07) | Health hazard / hazardous to the ozone layer | Acute toxicity Cat. 4; skin and eye irritation Cat. 2; skin sensitisation; single-exposure target organ toxicity Cat. 3; hazardous to the ozone layer |
| Health hazard, the silhouette (GHS08) | Serious health hazard | Respiratory sensitisation; germ cell mutagenicity; carcinogenicity; reproductive toxicity; single- and repeated-exposure target organ toxicity Cat. 1–2; aspiration hazard |
| Environment (GHS09) | Hazardous to the environment | Hazardous to the aquatic environment (Acute 1; Chronic 1, 2) |
Sources: legislation.gov.uk, Reg. 1272/2008 Annex V; HSE
How to read a label:
- More than one symbol: a single product's label can carry several pictograms (HSE).
- The symbol alone isn't enough: HSE says to read the hazard statement on the packaging and the safety data sheet. Sections 2 and 16 of the safety data sheet describe the dangers. Sections 4–8 cover emergencies, storage and handling (INDG136, p.3).
- Wording on the label: CLP labels include a signal word, "Danger" or "Warning". Hazard statements and precautionary statements replaced the old risk and safety phrases (HSE, COSHH, CLP and REACH).
- Old symbols: older stock may still show the earlier European symbols. These included Toxic/Very toxic, Harmful, Irritant, Highly/Extremely flammable and Dangerous to the environment. HSE says the current pictograms look similar but have a new shape, design and colour (HSE; INDG136, p.3).
- Products without a safety data sheet: medicines, pesticides and cosmetics fall under other legislation and don't come with one (INDG136, p.3).
I can look up the legally binding GB classification and pictograms for a specific substance on HSE's GB Mandatory Classification and Labelling list if that would help.
Why did the old orange square symbols change?
The orange-square symbols were replaced because the EU, and so Great Britain, adopted the UN's Globally Harmonised System (GHS), which uses the diamond pictograms. The CLP Regulation (EC) No 1272/2008 repealed the two directives behind the old labels, Directives 67/548/EEC and 1999/45/EC. GB CLP keeps that same text [1]. The regulation's recitals give the reasons.
Approach: I read the recitals of the CLP Regulation (the EU text and the GB retained text), HSE's COSHH Approved Code of Practice (L5) and the Irish HSA's CLP guidance. None of them explains why the colour or shape changed. They explain why the whole labelling system was replaced.
Why the system changed (CLP recitals)
- One system for global trade: Trade in chemicals is global, so companies should benefit from shared classification and labelling rules. Those rules should also match the rules for transport [1].
- The UN GHS: The UN spent 12 years developing harmonised criteria "with a view to facilitating worldwide trade while protecting human health and the environment". The result was the GHS [2].
- The same warnings for everyone: Workers and consumers worldwide "would benefit from a globally harmonised hazard communication tool in the form of labelling". So labels were rebuilt around the core GHS elements: hazard pictograms, signal words, hazard statements and precautionary statements [3].
- Encouraging other countries: The benefits grow as more countries adopt the GHS. The EU wanted to be "at the forefront" so others would follow [1].
- No loss of protection: The new rules were to build on 40 years of experience with the earlier EU legislation and keep the level of protection it had achieved [1].
What changed on the label
- Pictogram design: A black symbol on a white background inside a red frame, taking up at least one fifteenth of the label and at least 1 cm² [4]. As noted last time, HSE describes the new pictograms as similar to the old ones but with a new shape, design and colour (HSE).
- Wording: Hazard statements and precautionary statements replace the old risk and safety phrases. For example, H350 "may cause cancer" replaces the old cancer risk phrases such as R45 [5].
When it happened CLP took legal effect on 20 January 2009, with a long transitional period. It was phased in until 1 June 2015, when it came fully into force [5]. That is why older stock in some workplaces can still carry orange-square labels.
How do I know which symbol a chemical should have in the UK?
In Great Britain, the symbol comes from the chemical's classification under GB CLP, and the classification decides it in two ways. If the substance has an entry on HSE's GB Mandatory Classification and Labelling (GB MCL) list, you must classify it according to that entry [6]. For hazards the list doesn't cover, and for any substance or mixture not on it, the manufacturer, importer or downstream user classifies it themselves against the criteria in Annex I. Each classification then maps to a set pictogram [7]. If you're a user rather than a supplier, you read the symbols from the supplier's label and safety data sheet.
Approach: I read the GB CLP Regulation (the retained text as it applies in Great Britain), HSE's GB MCL list and HSE's COSHH Approved Code of Practice (L5).
Step 1: Check the GB MCL list first
- If a substance has a GB MCL entry, you must use that classification. You don't do your own classification for the hazard classes the entry covers. You still have to classify any other hazards yourself [6].
- HSE (named in the Regulation as "the Agency") must keep and publish this list of mandatory classifications and labelling [8].
- Each entry gives the pictograms directly. Benzene (EC 200-753-7) is listed as Flam. Liq. 2, Carc. 1A, Muta. 1B, STOT RE 1, Asp. Tox. 1, Eye Irrit. 2 and Skin Irrit. 2. Its labelling is GHS02, GHS08 and GHS07, with the signal word "Danger" [9].
Step 2: Otherwise, the supplier classifies it
- Manufacturers, importers and downstream users must classify a substance or mixture before placing it on the market [6].
- They gather the available information: test data, human and occupational experience, and new science. That information must relate to the form in which the product is sold and used. They then check it is adequate and reliable [10].
- Mixtures can be assessed on data for the mixture itself or for its ingredients. Carcinogenicity, mutagenicity and reproductive toxicity are judged on the ingredient data [11].
- They then apply the Annex I criteria for each hazard class. They use weight of evidence where the criteria can't be applied directly, and bridging principles for mixtures [12].
- Distributors and downstream users in Great Britain may rely on a classification made further up the supply chain. A downstream user can do so only if they don't change the composition [6].
Step 3: Turn the classification into pictograms
- The Annex I tables give the pictogram for each hazard class and category. Annex V sets out the design [7]. That mapping is the table from my first answer.
- Pictograms go on the label with the signal word, hazard statements and precautionary statements. The label must be in English [13].
Step 4: Apply the precedence rules Article 26 removes symbols that would duplicate others [14]:
- GHS06 (skull and crossbones) applies: GHS07 (exclamation mark) is left off.
- GHS05 (corrosion) applies: GHS07 is left off for skin or eye irritation.
- GHS08 applies for respiratory sensitisation: GHS07 is left off for skin sensitisation and for skin or eye irritation.
- GHS01 (exploding bomb) applies: GHS02 and GHS03 become optional, unless more than one of them is compulsory.
- GHS02 or GHS06 applies: GHS04 (gas cylinder) becomes optional.
- Several categories in one hazard class: only the pictogram for the most severe category is used. This also applies where a GB MCL entry is combined with your own classification.
Pyromellitic dianhydride shows these rules at work. It is classified Eye Dam. 1, Resp. Sens. 1 and Skin Sens. 1 but labelled only GHS08 and GHS05, with no exclamation mark [15].
Exceptions
- Very small or awkwardly shaped packaging can carry the label elements in another form, and in some cases a reduced set, under Annex I section 1.5 [16].
As an employer under COSHH You don't classify the products you buy. Suppliers must provide safety data sheets with the hazard details and general precautions, and you use them for your COSHH assessment [17]. Your employees must be allowed to see the relevant safety data sheets [18].
If you give me a substance name, CAS or EC number, I can look up its GB MCL entry and the pictograms it requires.