GHS Pictogram Meanings
What do the GHS pictograms mean?
There are nine GHS hazard pictograms, GHS01 to GHS09. Each one stands for a set of hazard classes and categories, and a pictogram goes on the label only when the chemical is classified in one of those categories. The breakdown below comes from EU CLP Annex V, the EU's legal text that puts the GHS pictograms into law (current consolidated text, version dated 1 July 2026). Annex V says the pictograms "shall" conform to the symbols and format of the specimens it shows [1].
| Code | Symbol | What it signals (hazard classes / categories) |
|---|---|---|
| GHS01 | Exploding bomb | Unstable explosives; Explosives of Divisions 1.1 to 1.4; self-reactive substances and mixtures Types A, B; organic peroxides Types A, B |
| GHS02 | Flame | Flammable gases 1A, 1B; aerosols 1, 2; flammable liquids 1 to 3; flammable solids 1, 2; self-reactives Types B to F; pyrophoric liquids/solids 1; self-heating 1, 2; substances that give off flammable gases in contact with water 1 to 3; organic peroxides Types B to F; desensitised explosives 1 to 4 |
| GHS03 | Flame over circle | Oxidisers: oxidising gases 1; oxidising liquids and solids 1 to 3 |
| GHS04 | Gas cylinder | Gases under pressure (compressed, liquefied, refrigerated liquefied, dissolved) |
| GHS05 | Corrosion | Corrosive to metals 1; skin corrosion 1 (1A, 1B, 1C); serious eye damage 1 |
| GHS06 | Skull and crossbones | Acute toxicity (oral, dermal, inhalation), categories 1 to 3 |
| GHS07 | Exclamation mark | Acute toxicity category 4; skin irritation 2; eye irritation 2; skin sensitisation 1, 1A, 1B; STOT single exposure 3 (respiratory tract irritation, narcotic effects); also hazardous to the ozone layer 1 |
| GHS08 | Health hazard | Respiratory sensitisation 1, 1A, 1B; germ cell mutagenicity 1A, 1B, 2; carcinogenicity 1A, 1B, 2; reproductive toxicity 1A, 1B, 2; STOT single exposure 1, 2; STOT repeated exposure 1, 2; aspiration hazard 1 |
| GHS09 | Environment | Hazardous to the aquatic environment: Acute 1, Chronic 1, Chronic 2 |
Things that often catch people out:
- One symbol, different meanings. GHS05 covers both physical corrosion (to metals) and health corrosion (skin and eyes). GHS07 is used for health effects and for ozone-layer hazard [1][2].
- GHS06 vs GHS07 for acute toxicity. The skull is for categories 1 to 3. Category 4 gets the exclamation mark instead [1].
- GHS08 marks chronic or serious systemic effects such as CMR (carcinogenic, mutagenic, toxic to reproduction), respiratory sensitisation and aspiration. Skin sensitisation is under GHS07 instead [1].
- Some classified hazards get no pictogram at all. These are Explosives Divisions 1.5 and 1.6, Flammable gases Category 2, Aerosols Category 3, self-reactives and organic peroxides Type G, and the reproductive-toxicity "effects on or via lactation" category [1]. The same goes for Aquatic Chronic 3 and 4 [2].
Approach: I read Annex V (Hazard Pictograms) of the current consolidated EU CLP Regulation (EC) No 1272/2008. Other GHS-based systems (GB CLP, US OSHA HazCom, and so on) use the same nine symbols, but I have not checked here whether their category assignments match exactly. Transport pictograms (ADR, IMDG, IATA) are a separate system and are not covered here.
Why does OSHA use fewer pictograms?
OSHA doesn't have fewer pictograms. The Hazard Communication Standard (HCS) only makes eight of the nine mandatory. The ninth, Environment (GHS09, used for aquatic toxicity), is marked "Non-Mandatory" in OSHA's pictogram table. OSHA notes that "This hazard is included in the GHS and it is not prohibited to include it on labels under the HCS" [3]. OSHA's own pictogram download page also offers all nine symbols, Environment included (OSHA, Hazard Communication Pictograms).
Why the environment symbol is optional: Neither OSHA source I opened states the reason in so many words. Two things in OSHA's enforcement directive for HCS 2024 (CPL 02-02-079) explain the pattern:
- What the standard covers. The directive describes the HCS as applying to hazardous chemicals that "may pose a physical or health hazard … to workers" [4]. Its classification appendices are Health Hazard Criteria (Appendix A) and Physical Hazard Criteria (Appendix B) [5]. Aquatic toxicity is neither, so nothing triggers a required environment pictogram.
- Voluntary use is allowed. Manufacturers, importers and distributors "can also choose to list the environmental effects and use the environmental pictogram on the label, if applicable, so long as the additional information does not impede the required information" [6].
Compared with EU CLP (from the previous answer): In the EU, GHS09 is required for Aquatic Acute 1 and Chronic 1 and 2. In the US, an HCS label for the same chemical can leave it off and still comply. The same label can carry it if you want one label for both markets.
Related OSHA label rules from the directive:
- On shipped containers, each pictogram may appear only once, even if several classifications call for it [7].
- Pictograms "must have a white background with a red border." Blank red diamonds are not allowed [7].
- The exclamation mark "is permitted (but not required)" for hazards not otherwise classified (HNOC), as long as "Hazard Not Otherwise Classified" or "HNOC" appears below it [7].
Approach: I used OSHA's enforcement directive for the 2024 HCS update (CPL 02-02-079), including its pictogram appendix, and OSHA's official pictogram page. The HCS regulatory text itself (29 CFR 1910.1200 and its Appendix C) is not in the datasets I can search, so the points above come from OSHA's directive and web page rather than the CFR text.