CLP hazard classes
Categories of types of hazard standardised by the CLP Regulation Annex I. 28 classes divided into physical, human-health, environmental and EU-supplementary hazards in accordance with the UN GHS.
Context
CLP hazard classes are the categories of types of hazard standardised by the CLP Regulation Annex I. They establish the scientific criteria for classifying a substance or chemical mixture in accordance with the UN GHS system.
Regulatory origin
Regulation (EC) 1272/2008 (CLP) Annex I. 28 hazard classes divided into physical, human-health, environmental and EU-supplementary hazards.
The 28 CLP hazard classes
16 classes of physical hazards (explosives, flammables, oxidisers, gases under pressure).
10 classes of health hazards (acute toxicity, corrosion, sensitisation, CMR carcinogenicity/mutagenicity/reproduction).
1 aquatic environmental class (hazard to the aquatic environment).
1 ozone-layer class.
Timeline
CLP adopted
Regulation (EC) 1272/2008 establishes the 28 hazard classes.
Substances
Full application for substances.
Mixtures
Full application for mixtures.
CLP+ Reg. 2024/2865
Added 4 new classes ED-HH, ED-ENV, PBT/vPvB, PMT/vPvM.
Progressive application
The new classes are applied progressively depending on whether it is a new or existing substance/mixture.
Applied case
A textile brand classifies the CLP classes critical for its sector and prioritises alternatives for the CMR ones.
Identifies critical classes for textiles: CMR 1A/1B (REACH Annex XVII entry 72), skin/respiratory sensitisation (colorants, retardants), aquatic hazard (dyeing discharges).
Audits the catalogue of chemical inputs against each critical class.
Substitution plan: 12 CMR products substituted in 2024-2025 · 8 sensitising products planned for 2026.
Surveillance of the new ED-HH/ED-ENV classes: cross-checks the catalogue with initial candidates to anticipate reclassifications.
Common mistakes
Class is not the same as category.
The class is the general type of hazard (e.g. carcinogenicity). The category is the severity within the class (Carc. 1A confirmed, Carc. 1B presumed, Carc. 2 suspected). 28 classes with internal categories. The complete classification requires class + category.
Not all classes trigger labelling.
Some classes do not have a pictogram assigned in CLP (e.g. minor hazards). Others have a pictogram + signal word + mandatory H/P statements. The label only carries the elements corresponding to the assigned classes/categories.
CLP classes are distinct from the categories of the pharma CMR Convention.
The CMR categories of CLP (Carc 1A/1B/2 · Muta 1A/1B/2 · Repr 1A/1B/2) are from the GHS-CLP system. They are NOT the IARC categories (1/2A/2B/3/4) nor those of the pharma CMR Convention. A frequent confusion — always verify the regulatory source.
The new ED/PBT/PMT classes are in transition.
CLP+ (Regulation 2024/2865) introduced new classes: ED-HH (endocrine disruptor, human health), ED-ENV (environmental), PBT/vPvB, PMT/vPvM. Progressive application: new substances from 1 May 2025; existing substances from 1 May 2026; new mixtures from 1 May 2026; existing mixtures 1 May 2028. Reclassification of inventories is mandatory.
Frequently asked questions
What are CLP hazard classes?
Categories of types of hazard standardised by Regulation (EC) 1272/2008 on the classification, labelling and packaging of substances and mixtures (CLP, OJEU L 353, 31.12.2008) Annex I. They establish the scientific criteria for classifying a substance or chemical mixture in accordance with the UN GHS system: physical hazards, human-health hazards, environmental hazards and EU-specific additional hazards.
How many hazard classes are there in CLP?
28 hazard classes divided into 16 physical (Annex I part 2 — explosives, flammables, oxidisers, gases under pressure, etc.), 10 for health (part 3 — acute toxicity, corrosion, sensitisation, CMR carcinogenicity/mutagenicity/reproduction), 1 aquatic environmental (part 4) and 1 ozone layer (part 5). In 2024-2026 Reg. (EU) 2024/2865 adds 4 new classes: ED-HH/ED-ENV/PBT-vPvB/PMT-vPvM with progressive application.
What is the difference between a CLP hazard class and category?
CLASS = the general type of hazard (e.g. carcinogenicity as a concept). CATEGORY = the severity or evidence within the class (e.g. Carc. 1A confirmed in humans by epidemiological evidence, Carc. 1B presumed in humans by robust animal evidence, Carc. 2 suspected by limited evidence). The complete CLP classification requires both dimensions — Art. 13 CLP. CLP Annex VI lists the mandatory harmonised classifications.
Which CLP classes are critical for textiles?
CMR 1A/1B (carcinogenicity/mutagenicity/reproductive toxicity) — critical due to the application of REACH Annex XVII entry 72 which prohibits CMR 1A/1B in textiles intended for skin contact since 1 Nov 2020 (Reg. (EU) 2018/1513); skin sensitisation H317 and respiratory H334 (reactive dyes, flame retardants, wetting agents); aquatic hazards H400/H410 (dyeing discharges without treatment). The new ED-HH/ED-ENV classes expand the regulatory scope.
How is the CLP classification of a mixture done?
Through the methods of CLP Annex I in order of preference: (i) own test data on the mixture when available, (ii) bridging extrapolation principles between similar mixtures in accordance with Section 1.1.3 of Annex I CLP, (iii) calculation based on the classification of the components via summation or multiplier formulas depending on the category. Each hazard is assessed separately. Documented in the Safety Data Sheet (SDS) Section 2 in accordance with REACH Annex II.
Fuentes oficiales
- European Parliament and Council · OJEU L 35331 dic 2008Regulation — legislation in force
- European Parliament and Council6 nov 2024Amending regulation
- European Chemicals Agency2024Official technical guidance
