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Classification

CLP vs UN GHS vs OSHA HazCom: what differs and where it applies

Hazard classes and categories adopted by EU CLP, GB CLP and OSHA HazCom versus the UN GHS, EU-only classes, mixture rules and labels.

Updated: 8 min read

Contents
  1. What the GHS is, and what it is not
  2. Who applies which version
  3. Hazard classes and categories: where they diverge
  4. EU-only additions: new hazard classes and EUH statements
  5. Mixture rules: ATE and concentration limits
  6. Labels: same pictograms, different rules around them
  7. Which one applies to my product?
  8. Frequently asked questions
  9. Sources

In short: The UN GHS is a model, not a law. The EU (CLP Regulation), Great Britain (GB CLP) and the United States (OSHA HazCom, 29 CFR 1910.1200) each turned it into law, picking different "building blocks" and different revisions. The result: the same mixture can be Acute Tox. 4 in one market and unclassified in another, a flammable liquid in the US but not in the EU, or carry an EU-only hazard statement. Classify separately for each market you sell into.

What the GHS is, and what it is not

The Globally Harmonized System of Classification and Labelling of Chemicals is published by the United Nations and revised every two years. The eleventh revised edition (GHS Rev. 11) was published in 2025; UNECE expects Rev. 12 in 2027. The GHS defines hazard classes, the categories inside each class, the criteria for each category and the label elements (pictogram, signal word, hazard and precautionary statements) that go with them.

The GHS is voluntary. Countries apply it through their own legislation and are free to adopt only some classes or categories. This is the "building block" approach, and it is the root of every difference described below. A second source of differences is timing: each jurisdiction aligns with a particular GHS revision, and revisions change criteria and statements.

Who applies which version

MarketLegal textGHS basisNotes
EU / EEA, Northern IrelandCLP, Regulation (EC) No 1272/2008, regularly amended by adaptations to technical progress Updated in steps by ATPs; not tied to one revisionAdds EU-only hazard classes and EUH statements
Great BritainGB CLP (retained Regulation 1272/2008)CLP as it stood at the end of 2020, then GB decisions Separate GB mandatory classification list
United States (workplace)OSHA HazCom, 29 CFR 1910.12002012 rule: GHS Rev. 3; 2024 rule: primarily Rev. 7, some Rev. 8 elements Environmental classes not adopted; US-specific classes added

OSHA's 2024 final rule (89 FR 44144, 20 May 2024) took effect on 19 July 2024. Under paragraph (j) as currently in force, suppliers must reclassify and update labels and SDSs for substances by 19 May 2026 and for mixtures by 19 November 2027.

Hazard classes and categories: where they diverge

Hazard classGHS (model)EU CLPOSHA HazCom
Acute toxicityCategories 1 to 5Categories 1 to 4Categories 1 to 4
Skin corrosion / irritation1 (1A, 1B, 1C), 2, 3 (mild)1 (1A, 1B, 1C), 21 (1A, 1B, 1C), 2
Serious eye damage / eye irritation1, 2A, 2B1, 21, 2A, 2B
Flammable liquidsCategories 1 to 4Categories 1 to 3Categories 1 to 4 (Category 4: flash point above 60 °C and up to 93 °C)
Aspiration hazardCategories 1 and 2Category 1Category 1
Hazardous to the aquatic environmentAcute 1 to 3, chronic 1 to 4Acute 1, chronic 1 to 4Not adopted (outside OSHA's remit)
Hazardous to the ozone layerCategory 1Category 1Not adopted
Endocrine disruption, PBT/vPvB, PMT/vPvMNot in the GHSEU hazard classes since Regulation (EU) 2023/707Not adopted
Combustible dust, simple asphyxiants, hazards not otherwise classifiedNot GHS classesNot CLP classesUS-specific additions defined in the standard

Two consequences show up most often on real SDSs. A diesel-type liquid with a flash point between 60 °C and 93 °C is a Category 4 flammable liquid in the US ("Combustible liquid", H227 with signal word "Warning") but is not classified as flammable under CLP. And a mixture with an acute toxicity estimate in the 2000 to 5000 mg/kg range is Acute Tox. 5 under the full GHS, yet neither CLP nor OSHA has that category, so the mixture is unclassified for that endpoint in both markets.

EU-only additions: new hazard classes and EUH statements

CLP has always gone beyond the GHS in places, mainly through supplemental EUH statements (for example EUH066, repeated exposure may cause skin dryness or cracking). Commission Delegated Regulation (EU) 2023/707 went further and created new hazard classes that have no GHS or OSHA equivalent: endocrine disruption for human health and for the environment, PBT/vPvB, and PMT/vPvM, with the statements EUH380, EUH381, EUH430, EUH431, EUH440, EUH441, EUH450 and EUH451. According to ECHA, new substances must apply them from 1 May 2025 and new mixtures from 1 May 2026, with transitional periods for products already on the market (substances until 1 November 2026, mixtures until 1 May 2028).

A US SDS will never carry these statements; an EU SDS for an affected product must. If you maintain one data set for both markets, keep the EU-only classifications as a separate layer. Our guide on how to read H and P codes explains the EUH series.

Mixture rules: ATE and concentration limits

For acute toxicity of mixtures, CLP and OSHA both use the GHS additivity formula, which combines the acute toxicity estimates (ATEs) of the relevant ingredients. Both also correct the formula when ingredients of unknown acute toxicity exceed 10 % of the mixture (CLP Annex I, 3.1.3.6; OSHA Appendix A, A.1.3.6.2.4). Because the categories differ, the same calculated ATE can lead to a different outcome only at the edges: for example, an oral ATEmix of 3000 mg/kg is unclassified in both, while the full GHS would give Category 5.

The bigger divergence is in concentration limits. CLP has harmonised classifications in Annex VI, Table 3, some with specific concentration limits (SCLs) and M-factors that bind every EU supplier. The US has no equivalent binding list; manufacturers classify from available data. So a mixture containing a substance with a low EU SCL can be classified in the EU at a concentration where the US classification, based on generic cut-offs, stays lower. Under REACH Annex II as amended by Regulation (EU) 2020/878, SCLs, M-factors and ATEs must also be shown in Section 3 of the EU SDS where available. Our guide on CLP mixture classification walks through the EU calculation.

Labels: same pictograms, different rules around them

  • Pictograms: the nine GHS pictograms are shared (see the 9 hazard pictograms). OSHA does not require the environment pictogram, because it does not regulate environmental hazards; CLP requires it for aquatic hazard categories that call for it.
  • Precedence rules differ in detail, for example when the exclamation mark is dropped. Check each regime's own table instead of copying a label.
  • Formatting: Regulation (EU) 2024/2865 revised CLP and introduced minimum font sizes and other formatting rules for EU labels. Regulation (EU) 2025/2439 later postponed the application of several of these labelling provisions to 1 January 2028. OSHA sets no comparable font-size table.
  • Language: CLP labels must be in the official language(s) of the Member State where the product is placed on the market (CLP Article 17(2)); HazCom labels must be in English, other languages may be added.

Which one applies to my product?

The rule follows the market, not the manufacturer's location. A product made anywhere and placed on the EU market is classified and labelled under EU CLP. A product supplied in England, Scotland or Wales follows GB CLP; in Northern Ireland, EU CLP. A product shipped to US workplaces follows OSHA HazCom; consumer products in the US fall under other agencies' rules, which this article does not cover. If you sell into several markets, you need one classification per regime and usually one SDS and label per market. For the SDS side, see SDS requirements in the EU, UK and US compared.

Frequently asked questions

Is a GHS-compliant SDS automatically CLP-compliant?

No. "GHS-compliant" has no legal meaning on its own. CLP omits some GHS categories and adds EU-only classes and EUH statements, so the classification must be checked against CLP itself.

Why does my US SDS show H227 when the EU SDS shows no flammability?

OSHA adopted flammable liquids Category 4 (flash point above 60 °C and up to 93 °C); CLP did not. Both sheets can be correct for their own market.

Do I need aquatic toxicity on a US SDS?

Section 12 must be present, but OSHA does not enforce its content and does not classify environmental hazards. Many suppliers still include the data because customers and other agencies ask for it.

This article is a comparison for orientation only; it is not legal advice. The consolidated legal texts prevail.

Sources

Related codes

H and P statements related to this topic; each is explained in the glossary with its full wording, thresholds and label use.

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