- The GHS has nine pictograms: a black symbol on a white background inside a red diamond border.
- Canada uses eight of them plus its own biohazardous infectious materials pictogram, and does not require the environment pictogram.
- OSHA treats the environment pictogram as optional; the EU and GB require it.
- Precedence rules stop some pictograms appearing together, such as the exclamation mark alongside the skull and crossbones for acute toxicity.
Hazard pictograms are the fastest way to communicate a hazard, which is why they appear both on the label and in section 2 of the SDS. Under the GHS, each one is a black symbol on a white background inside a red diamond border. The symbols are the same everywhere. Which ones are required, and for which hazards, differs slightly between markets.
GHS01Exploding bombExplosives; self-reactive substances and organic peroxidesAll four marketsGHS02FlameFlammable gases, aerosols, liquids and solids; pyrophoric and self-heating substances; substances that release flammable gas in contact with waterAll four marketsGHS03Flame over circleOxidising gases, liquids and solidsAll four marketsGHS04Gas cylinderGases under pressure, and chemicals under pressure in Canada and the USAll four marketsGHS05CorrosionSkin corrosion, serious eye damage, corrosive to metalsAll four marketsGHS06Skull and crossbonesAcute toxicity, categories 1 to 3All four marketsGHS07Exclamation markAcute toxicity category 4, skin and eye irritation, skin sensitisation, respiratory irritation, drowsiness or dizziness; ozone layer hazard in the EU and UKAll four marketsGHS08Health hazardRespiratory sensitisation, germ cell mutagenicity, carcinogenicity, reproductive toxicity, target organ toxicity, aspiration hazardAll four marketsGHS09EnvironmentHazardous to the aquatic environmentRequired in the EU and UK · optional in the US · not used in WHMISWHMISBiohazardous infectious materialsMicroorganisms, nucleic acids or proteins that cause infection in people or animalsCanada only (WHMIS)Which markets use which pictograms
- Canada (WHMIS 2015): eight GHS pictograms, plus the biohazardous infectious materials pictogram, which is unique to WHMIS. Environmental hazards are not part of WHMIS, so the environment pictogram is not required.
- United States (OSHA): eight pictograms are mandatory. The environment pictogram may be used but is not mandatory, because environmental hazards are outside OSHA's jurisdiction.
- EU and GB (CLP): all nine GHS pictograms. The EU's new hazard classes for endocrine disruptors, PBT and PMT substances have no pictogram; they are communicated with a signal word and EUH statements.
Precedence rules
A product can trigger several pictograms, but some combinations say the same thing twice. The GHS precedence rules, applied by OSHA (Appendix C of the standard) and by CLP (Article 26), remove the weaker symbol:
- If the skull and crossbones applies, the exclamation mark is not used for acute toxicity.
- If the corrosion pictogram applies, the exclamation mark is not used for skin or eye irritation.
- If the health hazard pictogram applies for respiratory sensitisation, the exclamation mark is not used for skin sensitisation or for skin or eye irritation.
Getting precedence wrong leaves a label with an extra pictogram that section 2 does not support, or one missing that should be there. Either way, the label and the SDS no longer match.
Signal words go with the pictograms
Every label with a pictogram also carries a signal word: Danger for the more severe hazard categories and Warning for the less severe. Only one signal word appears on a label. If any hazard calls for Danger, Danger is used.
Pictograms are not transport labels
The transport of dangerous goods uses its own diamond labels, coloured and with a class number at the bottom, set by the TDG Regulations in Canada, the DOT Hazardous Materials Regulations in the US and the ADR in Europe. A package can carry both: GHS pictograms for the people using the product, and transport labels for the carrier. They are not interchangeable, and section 14 of the SDS is where the transport classification belongs.
Sources
General information, not legal advice. Checked against the official sources above on 7 October 2026. Rules change: for your own products, ask for a spot-check.
