Globally Harmonized System (UN GHS): Complete Guide 2026

The Globally Harmonized System of Classification and Labelling of Chemicals (UN GHS) is the worldwide framework that defines how chemicals are classified, labeled, and described in Safety Data Sheets. Published by the United Nations Economic Commission for Europe (UNECE) and updated every two years, it standardizes hazard communication across borders so that a flammable liquid in Tokyo, Riyadh, or São Paulo is identified by the same pictogram, signal word, and hazard statement.

This guide is for compliance specialists, EHS managers, regulatory affairs professionals, and anyone tasked with classifying or labeling chemicals for international trade. It explains what the GHS is, how the Purple Book is structured, the changes introduced in the latest Revision 11 (September 2025), and which national regulations implement the system in each major market — from EU CLP and US OSHA HCS to China’s GB 30000 series and Indonesia’s Kemenperin rules.

At a glance

Full name: Globally Harmonized System of Classification and Labelling of Chemicals
Publisher: United Nations Economic Commission for Europe (UNECE)
First edition: December 2002 (published 2003)
Latest revision: Rev 11, published 12 September 2025 (document ST/SG/AC.10/30/Rev.11)
Revision cycle: Biennial (every two years)
Hazard groups: Three — physical, health, environmental
Standardized pictograms: 9
Status: Voluntary at UN level; binding only when adopted into national law
Country adoption: 80+ countries fully or partially implemented; UN target — universal implementation by 2030
Access: Electronic Purple Book free on UNECE website (English, French, Spanish initially; six UN official languages over time)

Background: from Rio 1992 to Rev 11

The GHS traces its origin to the 1992 UN Conference on Environment and Development (UNCED) in Rio de Janeiro, where governments agreed that a globally harmonized hazard classification and compatible labeling system should be available, if feasible, by the year 2000. A decade of technical negotiation followed, led by three international bodies: the International Labour Organization (ILO) for hazard communication, the Organisation for Economic Co-operation and Development (OECD) for health and environmental criteria, and a UN working group for physical hazards.

In December 2002, the UN Sub-Committee of Experts on the GHS formally adopted the first edition. UNECE published the Purple Book — the document’s informal name, drawn from its purple cover — in 2003. The 2002 World Summit on Sustainable Development in Johannesburg encouraged worldwide implementation by 2008.

The GHS has been revised every two years since:

Rev 1 (2005) — first revision after initial publication
Rev 2 (2007), Rev 3 (2009) — early refinements; Rev 3 became the reference for OSHA’s original HCS 2012
Rev 4 (2011) — adopted by Indonesia and several Asian markets as the legal baseline
Rev 5 (2013), Rev 6 (2015) — Rev 6 introduced Chapter 2.17 on desensitized explosives
Rev 7 (2017) — widely cited as a “settled” reference; basis of CLP, WHMIS 2015 amendments, and HCS 2024
Rev 8 (2019), Rev 9 (2021), Rev 10 (2023) — added subcategory refinements and label clarifications
Rev 11 (2025) — current edition; new atmospheric hazard class, non-animal skin sensitization methods, simplified precautionary statements

Each revision is based on amendments adopted by the Committee of Experts on the Transport of Dangerous Goods and on the GHS (CETDGGHS) at its biennial December sessions, then consolidated and published by UNECE the following September.

Who must comply with GHS

The GHS itself is voluntary at the international level — it is not a treaty, and no UN body enforces it directly. Compliance becomes binding only when a country adopts the system (or parts of it) into national law.

Once trading partners implement GHS, anyone in the chemical supply chain operating across borders is affected:

Manufacturers and importers classify substances and mixtures, prepare labels, and author Safety Data Sheets
Distributors and downstream users verify that received chemicals carry compliant labels and SDS
Logistics, transport, and warehousing operators rely on GHS classifications for storage segregation and shipping documentation
Employers train workers on the meaning of pictograms, signal words, and hazard statements
Regulators and enforcement bodies inspect labels and SDS, issue penalties for non-compliance

The practical implication: a manufacturer exporting from Germany to the United States, China, and Indonesia must produce labels and SDS that meet each country’s specific GHS implementation, including its building-block choices and country-specific deviations. There is no single “GHS-compliant” document — there are GHS-aligned documents tuned to each jurisdiction.

For substance-specific harmonized classifications and CAS-indexed hazard data, the Substance Database on ghssymbols.com provides access to EU CLP Annex VI entries, the most authoritative harmonized classification dataset in active regulatory use.

Structure of the Purple Book

The Purple Book is organized in four parts plus eleven annexes:

Part 1 — Introduction. Defines scope, terminology, hazard communication elements (labels, SDS), product identifiers, confidential business information rules, comprehensibility testing, and the building-block approach.

Part 2 — Physical hazards. Seventeen hazard classes covering explosives, flammable gases, aerosols, oxidizing gases, gases under pressure, flammable liquids, flammable solids, self-reactive substances, pyrophoric liquids, pyrophoric solids, self-heating substances, substances that emit flammable gas in contact with water, oxidizing liquids, oxidizing solids, organic peroxides, corrosive to metals, and (from Rev 6) desensitized explosives.

Part 3 — Health hazards. Ten hazard classes: acute toxicity, skin corrosion/irritation, serious eye damage/eye irritation, respiratory or skin sensitization, germ cell mutagenicity, carcinogenicity, reproductive toxicity, specific target organ toxicity — single exposure (STOT-SE), specific target organ toxicity — repeated exposure (STOT-RE), and aspiration hazard.

Part 4 — Environmental hazards. Historically two classes: hazardous to the aquatic environment (acute and chronic) and hazardous to the ozone layer. Rev 11 expanded this by replacing the narrow “ozone layer” class with a broader “Hazardous to the Atmospheric Environment/System” class that also covers substances contributing to global warming.

Annexes 1–11. Allocation of label elements (Annex 1), classification and labeling summary tables (Annex 2), codification of hazard and precautionary statements (Annex 3), SDS guidance (Annex 4), consumer product labeling (Annex 5), comprehensibility testing instrument (Annex 6), examples of label arrangements (Annex 7), classification examples (Annex 8), aquatic toxicity guidance (Annex 9), metal classification (Annex 10), and — new in Rev 11 — guidance on simple asphyxiants (Annex 11).

Hazard classes and hazard categories

Each hazard class describes the nature of the hazard (e.g., flammable liquid, carcinogen). Within each class, hazard categories rank severity — typically Category 1 is the most severe, with up to Category 5 in some classes. For flammable liquids, the four categories are distinguished by flash point and initial boiling point. For acute toxicity, five categories are defined by LD50 (oral, dermal) or LC50 (inhalation) values.

The building-block approach

A defining feature of the GHS is that countries are not required to adopt the entire system. Each competent authority chooses which hazard classes and categories to implement — these are the “building blocks.” The US OSHA HCS, for example, does not regulate environmental hazards. Australia does not adopt acute toxicity Category 5. The EU CLP adds country-specific EUH statements absent from the UN text. This flexibility eases adoption but creates the multi-jurisdictional complexity that compliance teams navigate daily.

The nine GHS pictograms

GHS pictograms are diamond-shaped symbols with a red border on a white background, conveying physical, health, and environmental hazards at a glance. There are nine standardized pictograms:

Code	Symbol	Hazard family
GHS01	Exploding bomb	Explosives, self-reactives, organic peroxides
GHS02	Flame	Flammables, pyrophorics, self-heating, emit flammable gas
GHS03	Flame over circle	Oxidizers
GHS04	Gas cylinder	Gases under pressure
GHS05	Corrosion	Skin/eye corrosion, corrosive to metals
GHS06	Skull and crossbones	Acute toxicity (Cat. 1–3)
GHS07	Exclamation mark	Irritation, sensitization, low acute toxicity
GHS08	Health hazard	CMR, STOT, respiratory sensitizer, aspiration
GHS09	Environment	Aquatic toxicity

Each pictogram appears on labels only when the chemical’s classification triggers it. SVG-quality reference images and full hazard mappings for each pictogram are available on individual pages such as GHS01 Exploding Bomb through GHS09 Environment.

The GHS does not define a biohazard pictogram — that symbol comes from BSL/laboratory biosafety standards, not from the Purple Book. Some national regulations (such as Canada’s WHMIS) add their own country-specific pictograms outside the nine UN-standard symbols.

Hazard communication elements

The GHS standardizes five elements that appear on every compliant label and in Section 2 of every SDS:

1. Product identifier. The chemical name, code, batch identifier, or commercial designation that unambiguously links the label to its SDS.

2. Signal word. One of two words — “Danger” for severe hazards (typically Category 1 and 2) and “Warning” for less severe hazards (typically Category 3 and 4). Only one signal word appears per label; “Danger” takes precedence when multiple categories apply.

3. Hazard statements. Standardized phrases coded with the letter “H” plus three digits. The first digit indicates the hazard type — 2 for physical, 3 for health, 4 for environmental. Examples: H220 (“Extremely flammable gas”), H350 (“May cause cancer”), H410 (“Very toxic to aquatic life with long-lasting effects”). The current GHS catalogues roughly 72 individual hazard statements plus 17 combined statements.

4. Precautionary statements. Coded with the letter “P” plus three digits, grouped into five categories — general (P1xx), prevention (P2xx), response (P3xx), storage (P4xx), and disposal (P5xx). The full catalogue includes around 116 individual statements and 33 combined statements. Rev 11 simplified and consolidated several precautionary statements to reduce label clutter.

5. Supplier identification. Name, address, and emergency phone number of the manufacturer, importer, or distributor placing the chemical on the market.

Together, these elements appear on labels affixed to containers and in Safety Data Sheets — the 16-section document that travels with the chemical through the supply chain. The 16-section SDS format is itself a GHS deliverable, standardized in Annex 4 of the Purple Book. For deeper coverage of SDS structure and authoring requirements by region, see the SDS pillar guide.

Revisions history: Rev 1 to Rev 11

The biennial revision cycle has refined the GHS continuously since 2003. Key milestones:

Rev 3 (2009). Refined classification for aspiration hazard and chronic aquatic toxicity. Became the reference for OSHA’s original HCS 2012 implementation in the United States, which remained in force until the 2024 update.

Rev 4 (2011). Added Chapter 2.16 on substances corrosive to metals. Adopted by Indonesia’s Ministry of Industry regulation No.23/M-IND/PER/4/2013, making it the legal baseline for chemical labeling in the Indonesian market through 2026.

Rev 5 (2013). Refined acute toxicity criteria for vapors.

Rev 6 (2015). Introduced Chapter 2.17 — Desensitized explosives as a new physical hazard class, addressing substances stabilized with phlegmatizers to suppress explosive properties.

Rev 7 (2017). Widely cited as a “settled” reference edition. Forms the basis of EU CLP (after subsequent ATPs), Australia’s WHS regulations effective January 2023, Canada’s WHMIS 2015 amendment, and OSHA’s HCS 2024 final rule.

Rev 8 (2019). Added subcategory 1A/1B for skin and respiratory sensitization; refined acute toxicity estimates for mixtures. Partially adopted by Health Canada in the January 2023 WHMIS amendment.

Rev 9 (2021). Updated guidance on classification of long-chain alkyl ester pesticides; minor labeling clarifications.

Rev 10 (2023). Published 27 July 2023. The immediate predecessor to current rules and the reference edition for many late-2024 regulatory updates worldwide.

Rev 11 (2025). Published 12 September 2025. The most consequential revision in years — new environmental class, non-animal sensitization testing pathway, and label simplification.

GHS Rev 11 (2025): what changed

Revision 11 was adopted at the 12th session of the CETDGGHS on 6 December 2024 and published by UNECE on 12 September 2025. The amendments are documented in ST/SG/AC.10/52/Add.3 and consolidated as ST/SG/AC.10/30/Rev.11. Eight substantive changes stand out:

1. New atmospheric environment hazard class. The narrow “Hazardous to the ozone layer” class (Chapter 4.2) is replaced by the broader “Hazardous to the Atmospheric Environment/System” class. Substances or mixtures containing at least 0.1% of an ingredient listed under the Montreal Protocol with measurable Global Warming Potential must now be classified, with a new hazard statement noting the contribution to global warming.

2. Aerosols and chemicals under pressure (Chapter 2.3). Clarified criteria for classifying aerosols. Aerosols are no longer covered by adjacent classes — Pressurized Chemicals (Section 2.3.2), Flammable Gases (Chapter 2.2), Pressurized Gases (Chapter 2.5), Flammable Liquids (Chapter 2.6), or Flammable Solids (Chapter 2.7) — eliminating overlap that previously caused inconsistent classification.

3. Skin sensitization (Chapter 3.4). New provisions support classification based on non-animal test methods, advancing the global shift toward animal-free toxicology. Defined in vitro and in chemico methods can now drive classification decisions without requiring animal studies in many cases.

4. Annex 11 — Simple asphyxiants. A new annex provides guidance on gases and vapors that displace oxygen, causing hypoxia in confined spaces. Distinguished from chemical asphyxiants (covered elsewhere as acute toxicity or STOT), simple asphyxiants are now recognized explicitly in hazard communication.

5. Precautionary statements rationalized. Restructured and simplified across all classes. Several near-duplicates merged, wording clarified, and label clutter reduced.

6. Annexes 9 and 10 (metals and aquatic toxicity). Updated to harmonize classification strategies for metals and metal compounds, especially regarding long-term aquatic toxicity assessment. References now align with Chapter 4.1.

7. Small container labeling flexibility. Greater flexibility introduced for containers of 100 mL or less, with special provisions for tiny packages (3 mL or less). Aimed at laboratory chemicals, single-dose products, and similar formats where full label content is physically infeasible.

8. Desensitized explosives (Chapter 2.17). Provisions clarified, particularly for handling and transport, building on the class introduced in Rev 6.

For a side-by-side comparison of Rev 10 versus Rev 11 with full deltas and adoption timeline, see UN GHS Rev 11 (2025): All Changes Explained.

Adoption by region

The GHS is implemented through national or regional regulations, each aligned with a different revision and each making its own building-block choices. Major markets:

European Union — CLP Regulation. Regulation (EC) No 1272/2008 on Classification, Labelling and Packaging implements GHS across all 27 EU member states plus EEA countries (Iceland, Liechtenstein, Norway). Adaptations to Technical Progress (ATPs) update CLP to track new GHS revisions. CLP adds EU-specific elements absent from the UN text, including EUH supplementary hazard statements, mandatory CLP Notification to ECHA, and the UFI / Poison Centre Notification system. See the EU CLP pillar guide.

United States — OSHA Hazard Communication Standard. OSHA HCS 2024 (29 CFR 1910.1200), finalized 20 May 2024, aligns the standard with UN GHS Rev 7. Key compliance dates: manufacturers, importers, and distributors — 19 January 2026 for substances and 19 July 2027 for mixtures; employers update workplace labeling and training by 20 July 2026 (substances) and 19 January 2028 (mixtures). The HCS does not regulate environmental hazards. Full breakdown in the OSHA HCS pillar guide.

Canada — WHMIS 2015. The Hazardous Products Regulations (HPR), most recently amended 4 January 2023, align Canada with GHS Rev 7 plus selected elements of Rev 8. Canada retains a unique Biohazardous Infectious Materials class outside the UN GHS framework. Health Canada is the federal authority; provincial occupational health and safety regulators enforce workplace requirements.

Australia — Model WHS Regulations. Fully transitioned to GHS Rev 7 effective 1 January 2023. Only Rev 7 may now be used for workplace classification and labeling across all states and territories. Safe Work Australia administers the model regulations; state and territory work-safety regulators enforce.

China — GB 30000 series. A suite of mandatory national standards aligned primarily with GHS Rev 4 historically, with newer parts incorporating Rev 10. GB 30000.30–2025 on desensitized explosives, published 30 June 2025, takes effect 1 July 2026 and brings China’s physical-hazard count to 29 classifications. The Standardization Administration of China (SAC) issues the standards; the Ministry of Emergency Management and provincial bodies enforce.

South Korea — MoEL regulations. The Ministry of Employment and Labor operates a centralized MSDS submission system. From 16 January 2021, MSDS submission is mandatory before import; the final compliance deadline for existing products is 16 January 2026. Overseas manufacturers may appoint a Korea-based Only Representative to handle submissions and Confidential Business Information (CBI) applications.

Japan — JIS Z 7252 / JIS Z 7253. Japan implements GHS through Japanese Industrial Standards covering classification (Z 7252) and labeling/SDS (Z 7253), aligned with Rev 6 and updating toward later revisions. The Ministry of Health, Labour and Welfare, Ministry of Economy, Trade and Industry, and Ministry of the Environment share enforcement under the Industrial Safety and Health Act, PRTR Law, and Poisonous and Deleterious Substances Control Law.

Indonesia — Ministry of Industry (Kemenperin). Implementation through Regulation No.87/M-IND/PER/9/2009 (initial GHS adoption, effective March 2010) and Regulation No.23/M-IND/PER/4/2013 (amended to Rev 4). National standards SNI 9030-1:2021 and SNI 9030-2:2021 based on Rev 7 exist but remain voluntary until further legislative action. Mandatory for all substances since 2010, all mixtures since 31 December 2016.

Brazil — ABNT NBR 14725:2023. The national standard published in 2023 aligns Brazil with Rev 7 of the GHS, replacing the previous 2009 version. Mandatory for all chemical substances and mixtures placed on the Brazilian market.

Other implementations include Türkiye (SEA Yönetmeliği — closely modeled on EU CLP), Saudi Arabia and the GCC (GSO 2017 standard), Taiwan (CCS / Toxic and Concerned Chemical Substances Control Act), Malaysia (CLASS Regulations 2013), Philippines (DENR rules), Singapore (Workplace Safety and Health Act plus Hazardous Substances), and Peru, Mexico, and Argentina (UN GHS directly or in transition).

A country-by-country status map with current revision in force, transition deadlines, and links to local clusters is maintained at GHS Implementation by Country: 2026 Status Map.

UN governance: how the GHS is maintained

The GHS is governed by a two-tier UN structure under the Economic and Social Council (ECOSOC):

Committee of Experts on the Transport of Dangerous Goods and on the GHS (CETDGGHS). The parent committee, meeting biennially in December. Adopts amendments and recommends them for publication as the next revision of the Purple Book.

Sub-Committee of Experts on the GHS (UNSCEGHS). The technical sub-committee, sitting twice a year (typically June/July and November/December). Develops proposals through informal working groups, peer reviews, and country submissions. The 48th session, held in 2025, reviewed proposals for the 2025–2026 biennium.

The UNECE Secretariat in Geneva coordinates meetings, manages publications, and maintains the official Purple Book on the UNECE website.

Country delegations participate through national focal points — the UK’s Health and Safety Executive (HSE), Germany’s BAuA, US OSHA and EPA, Japan’s METI, and equivalent bodies elsewhere. International organizations contribute technically: ILO on hazard communication, OECD on health and environmental criteria, ICCA representing industry, WHO and the International Council on Mining and Metals (ICMM) on specific topics.

The transparent process — every working paper is publicly downloadable from the UNECE website — gives industry and civil society direct visibility into upcoming amendments before they are adopted.

Implementation gaps and the 2030 target

Despite 23 years of revisions, GHS adoption remains uneven. Of roughly 195 countries worldwide, around 80 have implemented the system fully or partially. Coverage is highest in the EU, North America, East Asia, and Australia/New Zealand; weakest across much of Sub-Saharan Africa, parts of Central Asia, and several Pacific island nations.

The Global Framework on Chemicals — adopted in 2023 to replace the Strategic Approach to International Chemicals Management (SAICM) — sets Target B6: full GHS implementation by all governments by 2030, in all relevant sectors as appropriate to national circumstances.

A multi-stakeholder pilot project launched in June 2022 targets four African countries — Ghana, Kenya, Nigeria, and Côte d’Ivoire — with capacity building, draft legislation support, and regional knowledge transfer. The project is co-funded by the European Union, the UN Environment Programme, the UN Institute for Training and Research, and the International Council of Chemical Associations.

For manufacturers, the implication is straightforward: markets that lack GHS today are likely to adopt it within the next 5–7 years. Building GHS-aligned classification and SDS authoring capabilities now positions companies to access these markets as regulations come into force.

Key takeaways

The Globally Harmonized System is the UN framework that standardizes chemical hazard classification, labeling, and Safety Data Sheets worldwide
The system is voluntary at the international level but binding through national implementations such as CLP (EU), HCS 2024 (US), GB 30000 (China), WHMIS (Canada), and WHS (Australia)
The Purple Book is structured in 4 parts and 11 annexes, defining 17 physical, 10 health, and 2 environmental hazard classes (Rev 11 expanded environmental coverage to atmospheric hazards including global warming potential)
Hazard communication uses 9 pictograms, 2 signal words (Danger / Warning), H-statements, P-statements, and a 16-section SDS format
Rev 11 (12 September 2025) is the current edition — introduces atmospheric hazard class, non-animal sensitization testing, simplified precautionary statements, small container flexibility, and Annex 11 on asphyxiants
The system is maintained via the UNSCEGHS / CETDGGHS under UN ECOSOC, with biennial revisions; the UN target is universal implementation by 2030

Articles in this pillar

The UN GHS pillar covers the global framework and its country-by-country implementation. Direct deep-dives:

UN GHS Rev 11 (2025): All Changes Explained — side-by-side comparison of Rev 10 vs Rev 11, adoption timeline, practical impact
UN GHS Implementation by Country: 2026 Status Map — country-by-country table with current revision in force, transition deadlines, links to local regulations

Sister pillars covering specific national implementations:

Tools to act on this content:

Sources

UNECE — Globally Harmonized System of Classification and Labelling of Chemicals (GHS Rev. 11, 2025)
UNECE — About the GHS
UNECE — ECOSOC Sub-Committee of Experts on the GHS (48th session)
UNECE — GHS Implementation Status
UN Environment Programme — GHS Implementation under the Global Framework on Chemicals
ECHA — CLP Regulation EC 1272/2008 overview
OSHA — Hazard Communication Standard 29 CFR 1910.1200
Federal Register — HCS 2024 Final Rule, 89 FR 44144 (20 May 2024)
CCOHS — Globally Harmonized System (GHS)
Safe Work Australia — Globally Harmonized System and the model WHS laws
Health Canada — WHMIS Hazardous Products Regulations
PHMSA — Global Harmonization of Hazard Classification and Labeling Systems
PubChem (NIH) — GHS Classification Summary
UN Document ST/SG/AC.10/30/Rev.11 — Globally Harmonized System of Classification and Labelling of Chemicals, Eleventh Revised Edition (UN, Geneva, 2025)

Globally Harmonized System (UN GHS): Complete Guide 2026

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About UN GHS

UN GHS Rev 11 (2025): All Changes Explained

GHS by Country: Globally Harmonized System Map 2026