EU CLP and OSHA HazCom: comparing hazard classes and building blocks

Date every comparison, because both systems are moving. This one reflects the texts in force on 14 October 2026.

CLP's hazard criteria in Annex I follow GHS Revisions 6 and 7, adapted by Regulation (EU) 2019/521. Delegated Regulation (EU) 2023/707 added EU classes for endocrine disruption, PBT and vPvB, and PMT and vPvM. Regulation (EU) 2024/2865 changed the labelling rules, and Regulation (EU) 2025/2439 moved some of its dates. The CLP rules apply to substances and mixtures placed on the EU market, and labels must be in the official languages of each Member State where the product is sold.

OSHA's standard says it is consistent with the GHS, "primarily Revision 7". The 2024 update, published on 20 May 2024 and effective from 19 July 2024, also took some elements of Revision 8, such as chemicals under pressure. After a four-month extension published on 15 January 2026, manufacturers, importers and distributors had to comply for substances by 19 May 2026, and must comply for mixtures by 19 November 2027. Employers follow on 20 November 2026 for substances and 19 May 2028 for mixtures. Until those dates, companies may follow either the current text or the version in force before the update. OSHA's standard covers hazardous chemicals in US workplaces, with labels and safety data sheets in English.

A draft is pending on the EU side. The Commission notified a draft delegated regulation to the WTO on 17 August 2026 that would bring CLP in line with GHS Revisions 8 to 10, and partly with Revision 11. Comments close on 16 October 2026, adoption is planned for the fourth quarter of 2026, and the draft would apply 24 months after it enters into force.

Most physical hazard classes match category for category, including explosives, flammable gases, aerosols, oxidisers, self-reactive substances, organic peroxides, corrosive to metals and desensitised explosives. Three differences matter in practice. OSHA has a fourth flammable liquids category, for flash points above 60 °C and up to 93 °C, while CLP stops at Category 3. OSHA has chemicals under pressure, Categories 1 to 3, which CLP will gain only if the draft adaptation is adopted. Neither system adopts acute toxicity Category 5, skin irritation Category 3 or aspiration hazard Category 2.

Among health hazards, CLP has a single eye irritation Category 2, while OSHA allows 2A and 2B. CLP requires skin corrosion sub-categories 1A, 1B and 1C when the data allow, while OSHA makes them optional. Only CLP has endocrine disruption for human health, in two categories.

The environmental side differs most. CLP classifies hazards to the aquatic environment (acute and chronic, with M-factors), the ozone layer, endocrine disruption for the environment, PBT and vPvB, and PMT and vPvM. OSHA adopts none of these. Ecological information belongs in sections 12 to 15 of a US safety data sheet, which OSHA doesn't enforce.

OSHA has three hazards of its own. These are simple asphyxiants, combustible dust and hazards not otherwise classified (HNOC), which are effects found during classification that don't meet any class's criteria. CLP has no equivalent class for any of them.

The 2023/707 classes are now in force for substances placed on the EU market from 1 May 2025, and for mixtures from 1 May 2026. Products already on the market before those dates have until 1 November 2026 for substances and 1 May 2028 for mixtures.

CLP has a binding list. A substance with a harmonised classification in Annex VI must be classified according to that entry for the hazard classes it covers (Article 4(3)). Suppliers self-classify only the remaining classes, and must use any harmonised specific concentration limits, M-factors and acute toxicity estimates. OSHA has no binding classification list. Classifiers evaluate the evidence themselves, and may treat listings by the US National Toxicology Program or the International Agency for Research on Cancer as establishing a carcinogen.

Mixture cut-offs often differ. For a skin sensitiser Category 1 ingredient, OSHA classifies the mixture from 0.1% and CLP from 1.0%. For reproductive toxicants, OSHA uses 0.1% for Categories 1 and 2, while CLP uses 0.3% for Category 1A and 1B and 3.0% for Category 2. For a target organ toxicant Category 1 ingredient, OSHA classifies the mixture as Category 1 from 1.0%, while CLP gives Category 2 between 1% and 10% and Category 1 only from 10%.

The acute toxicity additivity formula also counts different ingredients. OSHA includes ingredients with an oral or dermal LD50 above 2,000 and up to 5,000 mg/kg. CLP counts only ingredients that fall into its acute toxicity categories, so the same mixture can reach Category 4 in the US and stay unclassified in the EU.

Take a fictional water-based degreaser made by Tarnwick, with a flash point of 70 °C. It contains 0.5% of an ingredient classified as a skin sensitiser Category 1 and 1% of an ingredient classified as a Category 2 reproductive toxicant, both without sub-categories.

Under OSHA, the mixture is a flammable liquid Category 4, a skin sensitiser Category 1 and a reproductive toxicant Category 2. Its US label needs the product identifier, signal word, hazard and precautionary statements, pictograms, and a US name, address and phone number, in English.

Under CLP, the same mixture meets none of those classifications. The flash point is above Category 3's limit, the sensitiser is below 1.0% and the reproductive toxicant is below 3.0%. Its EU label still needs the statement EUH208, "Contains (name of sensitising substance). May produce an allergic reaction", because the sensitiser is at or above 0.1% (Annex II, section 2.8). An unclassified mixture doesn't need a safety data sheet by default, but REACH Article 31(3) requires one on request because it contains a sensitiser and a reproductive toxicant at 0.1% or more.

The safety data sheets differ in format and enforcement too. The EU format is set by REACH Annex II, as replaced by Regulation (EU) 2020/878, in the official language of each Member State. The US format is OSHA's Appendix D, 16 sections in English, with sections 12 to 15 included but not enforced by OSHA.

Keep a classification record for each system rather than one record with a translation table. A translated result is unsafe wherever a cut-off differs, a class or category exists on one side only, or one side has a binding harmonised entry. That covers sensitisers, reproductive toxicants, Category 2 carcinogens, target organ toxicity, acute toxicity, flammable liquids above 60 °C, eye irritation, and every environmental and EU-only class.

For each product, record the edition of each text used, the date of the classification, the data relied on and the result per class. Mark the rows that will change on known dates. Those are the 2023/707 transition dates for products already on the market, the OSHA mixture dates of 19 November 2027 and 19 May 2028, and the EU's GHS adaptation once it is adopted. Re-check the EU records when a new Annex VI entry is adopted, because harmonised classifications override self-classification.