GHS

## Globally Harmonized System (GHS) The Globally Harmonized System of Classification and Labelling of Chemicals is the United Nations system for classifying chemical hazards and communicating them through standardised labels and safety data sheets. Developed under the UN Economic Commission for Europe, it provides the common building blocks that national regulations, such as the EU CLP Regulation and the US OSHA Hazard Communication Standard, implement. ### Key facts - GHS was adopted by the UN in 2002 and is published as the "Purple Book", now in its tenth revised edition, updated biennially by the UN Sub-Committee of Experts on GHS. - It defines hazard classes (physical, health, environmental) divided into categories of severity, with standardised pictograms, signal words, hazard statements and precautionary statements. - GHS is not directly law anywhere; it is a framework that countries implement through national regulations, choosing which building blocks to adopt. - The EU implements GHS through the CLP Regulation; the United States through OSHA's Hazard Communication Standard; many other countries through their own aligned regulations. - The system covers classification criteria, label elements, and the 16-section safety data sheet format that carries detailed hazard and handling information. - Implementation differs by jurisdiction: the same chemical can be classified differently in the EU, US and elsewhere because of different building block choices and update cycles. - GHS also underpins transport classification alignment, though dangerous goods transport follows its own modal regulations with related criteria. ### What the GHS is Before GHS, chemical hazard communication was a national patchwork: different symbols, different phrases, different classification criteria in every major market. A chemical considered flammable in one country might not be in another; a label that warned workers in Germany meant nothing to workers in Brazil. The UN created GHS to give the world one technical language for chemical hazards, so that a classification developed in one country could be understood everywhere. The system's architecture has three parts. Classification criteria define the hazard classes and the test data, bridging principles and cut-off values that assign chemicals to categories: flammable liquids category 1 through 4, acute toxicity categories 1 through 5, carcinogenicity categories 1A, 1B and 2, and so on across physical, health and environmental endpoints. Label elements translate classifications into communication: the diamond pictograms with red borders, the signal words Danger and Warning, the codified H and P statements. And safety data sheets carry the full information in a standardised 16-section format for professional users. The building block approach is the key to understanding GHS in practice. The UN offers the complete set of hazard classes, but each country decides which to adopt into law. The EU adopted most blocks with some additions; the US adopted a subset, excluding for example certain environmental hazards from mandatory classification. This is why "GHS compliant" is a jurisdiction-specific claim: compliant with which country's implementation, and which revision? ### Why it matters for market access GHS is the grammar of chemical market access worldwide. Every market's chemical labelling, safety data sheet and packaging rules are written in GHS terms, so a company selling chemicals internationally must produce jurisdiction-specific classifications, labels and data sheets from a common technical base. The classification work is done once per chemical; the communication is localised per market. The differences between implementations are where market access friction lives. A mixture classified as hazardous under EU CLP may not be classified under US HazCom, or vice versa, because of different building blocks, different concentration thresholds or different revision cycles. Labels, pictograms and statements must be generated per jurisdiction, in the required languages, and safety data sheets must follow each country's format and content rules. A single global label is generally impossible; multi-jurisdiction labelling strategies use modular label designs with jurisdiction-specific panels. GHS classifications also propagate into other market access requirements. Transport classification for dangerous goods uses related criteria; workplace safety rules reference GHS classifications for exposure controls; product-specific regulations, from toys to cosmetics to biocides, restrict substances based on their hazard classifications. The classification is therefore an input to decisions across the product portfolio, and changes in classification, from new data or a new GHS revision, can cascade through labels, data sheets, transport documents and product eligibility. ### Who it applies to GHS, through national implementations, applies to the chemical supply chain: - Chemical manufacturers, who classify the substances they produce according to the implemented criteria. - Importers, who classify the chemicals they bring into each jurisdiction under that jurisdiction's rules. - Formulators and downstream users, who classify mixtures from ingredient data using bridging principles and concentration limits. - Distributors and retailers, who must supply correctly labelled and documented chemicals. - Employers, who must maintain hazard communication programmes, train workers and make safety data sheets accessible under rules like OSHA HazCom. - Transport operators, who classify dangerous goods under the modal regulations that align with GHS criteria. The UN Sub-Committee of Experts maintains the system itself, with participation from governments, industry and labour organisations. National competent authorities implement and enforce it, coordinated through international cooperation but sovereign in their building block choices. ### Core requirements across implementations While details vary, GHS-based regimes share a common core. Classification. Suppliers classify each substance and mixture against the implemented hazard classes using test data, literature, bridging principles for mixtures, and generic concentration limits. New information must be evaluated and classifications updated. Labelling. Labels carry the supplier identification, product identifiers, GHS pictograms, signal words, hazard statements, precautionary statements and any supplemental information the jurisdiction requires. Labels must be in the required languages, legible, durable and firmly affixed. Safety data sheets. The 16-section SDS communicates hazards, composition, first aid, firefighting, handling, exposure controls, toxicological and ecological information, transport and regulatory status. It must be provided down the supply chain and kept current. Packaging. Packaging must safely contain the chemical, with child-resistant closures and tactile warnings where the implemented rules require. Training and workplace programmes. Worker protection implementations require employers to train workers on the label and SDS system, maintain written hazard communication programmes, and ensure access to information. | GHS element | Function | Implementation example | |---|---|---| | Hazard classes and categories | Standardised classification | EU CLP Annex I, OSHA HazCom appendices | | Pictograms | Visual hazard warning | Red-bordered diamonds on labels | | H and P statements | Codified phrases | H-statements for hazards, P for precautions | | Signal words | Severity flag | Danger or Warning | | 16-section SDS | Detailed information | Supplier to customer communication | ### Market access relevance Chemical market entry should start with a classification inventory: every substance and mixture mapped to its classification under each target jurisdiction's implemented GHS revision. This inventory drives labels, data sheets, packaging, transport classification and regulatory restrictions, so its accuracy determines the whole downstream chain. Localisation must be systematic. Labels and safety data sheets need jurisdiction-specific generation: the right building blocks, the right revision, the right languages, the right supplemental statements. Template systems that assemble compliant documents from the classification inventory are far more reliable than manual adaptation, and they handle revision updates efficiently. Revision tracking is a standing obligation. The UN updates GHS biennially, and jurisdictions adopt revisions on their own timetables: the EU through ATPs (adaptations to technical progress) to CLP, the US through OSHA rulemaking. Each adoption can reclassify chemicals and change label requirements, with transition periods that must be managed across inventory and documentation. Finally, treat GHS as the foundation for broader chemical compliance. REACH, TSCA, biocides, transport and workplace rules all build on or reference GHS classifications. Investment in classification quality pays across every regime that consumes it. ### Common misconceptions | Misconception | Reality | |---|---| | "GHS is a global law." | It is a UN framework implemented through national laws. There is no direct GHS legal obligation; obligations come from each country's implementation. | | "GHS classification is identical worldwide." | Building block choices, revision cycles and national additions produce different classifications for the same chemical across jurisdictions. | | "The SDS is the same everywhere." | The 16-section format is common, but content requirements, exposure limits and regulatory sections differ by country. | | "Small businesses are exempt." | Hazard communication duties apply regardless of company size. Some jurisdictions have simplified provisions, but the core duties remain. | | "If it is not classified, no SDS is needed." | Many jurisdictions require SDSs on request or for specific situations even for non-classified mixtures, and downstream customers often demand them contractually. | | "Pictograms are the whole label." | Pictograms are one element among signal words, statements, supplier identity and supplemental information. A pictogram alone is not a compliant label. | ### Frequently asked questions What is the Purple Book? The UN publication containing the GHS: classification criteria, label elements and SDS guidance. It is updated every two years by the Sub-Committee of Experts; the tenth revised edition is current. How do the EU and US implementations differ? Both use GHS building blocks, but the EU CLP Regulation adopts more hazard classes, including environmental hazards with specific EU additions, while OSHA HazCom adopts a subset focused on workplace hazards. Classifications, label details and SDS rules differ accordingly. Who maintains our classifications? The supplier placing the chemical on each market, under that market's rules. Manufacturers and importers classify; downstream users classify their mixtures; all must update with new information. Do we need an SDS for every product? SDSs are required for hazardous chemicals supplied to professional users under GHS implementations. Consumer products have labelling instead, and some jurisdictions require SDSs to be available on request even for non-classified products. How often must labels and SDSs be updated? When new hazard information emerges or when the implemented GHS revision changes classifications, within the transition periods set by each jurisdiction. Proactive monitoring of ATPs and rulemakings is essential. Does GHS cover nanomaterials? Classification criteria apply to the substance including nanoforms where data exists, and jurisdictions have added nano-specific provisions, such as EU requirements for nanoform characterisation. The science and rules continue to evolve. ### Sources - UNECE, about GHS: https://unece.org/about-ghs - US OSHA, Hazard Communication Standard: https://www.osha.gov/hazcom - Regulation (EC) No 1272/2008 on classification, labelling and packaging, EU GHS implementation (EUR-Lex): https://eur-lex.europa.eu/eli/reg/2008/1272/oj/eng