The UN GHS: Globally Harmonized System of Classification and Labelling

What the GHS is, and is not

The GHS is published by the United Nations in a document known as the "Purple Book" and is revised roughly every two years. Revision 10 is the edition on which the hazard and precautionary statement texts on this site are based; see our data sources. It does not itself regulate anyone. Countries and regions implement it through laws such as OSHA HazCom in the US, WHMIS in Canada and CLP in the EU. The overview of the system and its codes is on our GHS pages.

How it is organized

• Classification criteria. Hazard classes with categories for physical hazards (such as flammable liquids), health hazards (such as acute toxicity and skin corrosion) and environmental hazards (such as aquatic toxicity). See the hazard classes.
• Hazard communication. Label elements: pictograms (see pictograms), signal words (Danger and Warning), hazard statements (H-codes) and precautionary statements (P-codes).
• Safety data sheet. Annex 4 sets out the 16 sections and what each should contain. See the sections overview.
• Annexes. Further annexes cover allocation of label elements, codification of statements and precautionary statement guidance.

The building block approach and why systems differ

The GHS allows countries to adopt the "building blocks" they need. A country may leave out a hazard class or category, and may choose which revision to implement. This is why OSHA does not include environmental hazard classes or some categories such as acute toxicity Category 5, while the EU includes environmental classes and adds a few hazards of its own. The result is that the same chemical can have slightly different classification and labels in different countries, even though they all use the GHS vocabulary. Implementation also lags: countries update their rules to later revisions at different speeds. See Australia and Japan and China for other examples.

What GHS Annex 4 says about the SDS

Annex 4 provides the guidance on compiling an SDS. It specifies the 16 sections and their order: from identification (Section 1) through hazard identification, composition, first aid, fire-fighting, accidental release, handling and storage, exposure controls, physical and chemical properties, stability, toxicology, ecology, disposal, transport and regulatory information to other information (Section 16). Each section's pages on this site compare the OSHA and GHS content; start at Section 1. Annex 4 also explains how to write consistently and says the SDS should be dated and clear.

Key differences between the GHS and OSHA HazCom

• GHS is a recommendation; HazCom is binding law in the US.
• OSHA adopts a subset of GHS classes and categories, and does not enforce Sections 12 to 15 of the SDS.
• OSHA adds hazards that the GHS does not define in the same way, such as combustible dust and simple asphyxiants, and requires hazards not otherwise classified (HNOC) to be addressed.
• GHS includes environmental classes; HazCom does not.
• OSHA's rule follows a particular GHS revision: Revision 3 in the 2012 update and primarily Revision 7 in the 2024 update; other systems use different revisions.

Practical points

When reading a sheet, don't assume that "GHS compliant" means identical to the version in your country. Check that the sheet was prepared for your jurisdiction. For comparing classifications across sources, see how we choose the primary one in data sources. For labels, see chemical labeling requirements.

Frequently asked questions