Q.01

What is a harmonised classification under CLP?

A harmonised classification is a hazard classification for a substance that is set at EU level and written into Part 3 of Annex VI (Table 3) of the CLP Regulation (EC) No 1272/2008. Once a substance has an entry there, manufacturers, importers and downstream users must use it and shall not classify the substance themselves for the hazards that entry covers [1].

What it does in law (Article 4(3))

  • If a substance has an Annex VI Part 3 entry, it "shall be classified in accordance with that entry". You do not carry out a Title II self-classification for the hazard classes, differentiations, or forms or physical states that the entry covers.
  • The harmonised classification applies to all forms and physical states, unless the entry limits it to a specific one.
  • For hazards, forms or states the entry does not cover, you still have to self-classify under Title II [1]. In practice an entry is often only partly harmonised, and the rest of the classification falls to the supplier.

Which substances get one (Article 36)

  • Normally harmonised: substances meeting the Annex I criteria for:
    • respiratory sensitisation Cat. 1/1A/1B
    • germ cell mutagenicity, carcinogenicity or reproductive toxicity Cat. 1A, 1B or 2
    • endocrine disruption (human health or environment) Cat. 1 or 2
    • PBT or vPvB
    • PMT or vPvM [2]
  • Always harmonised: active substances in plant protection products (Regulation (EC) No 1107/2009) and biocidal products (Regulation (EU) No 528/2012) "shall be subject to" harmonised classification and labelling.
  • Case by case: any other hazard class "may" be added if the need for action at Community level is justified [2].

How a classification is harmonised (Article 37)

  1. Who can propose: a Member State competent authority "may" propose a harmonised classification, or a revision of one. The Commission may ask ECHA or EFSA to prepare a proposal. Manufacturers, importers and downstream users may also propose one, but only where Annex VI Part 3 has no entry for that hazard class or differentiation [3].
  2. Notifying an intention: the submitter must first notify ECHA that it intends to submit a proposal. ECHA publishes the substance and the status of the proposal within one week; this is the Registry of CLH intentions [3].
  3. RAC opinion: the Committee for Risk Assessment (RAC) "shall adopt an opinion within 18 months" of receiving the proposal, with an opportunity for comments [4].
  4. Commission decision: if the Commission finds harmonisation appropriate, it adopts a delegated act amending Annex VI Table 3 (an Adaptation to Technical Progress, or ATP). It acts "without undue delay", preferably before the end of the calendar year after the RAC opinion is published [4].
  5. Industry's duty to update: manufacturers, importers and downstream users with new information that may change an existing entry "shall submit a proposal" to a competent authority [4].

What an entry contains

  • An Annex VI Table 3 entry gives the substance's identity (Index No, EC No, CAS No and name), its hazard class and category codes, and its H-statements.
  • It also gives the label elements (pictogram, signal word, H-statements and supplemental H-statements), plus any harmonised specific concentration limits, M-factors or acute toxicity estimates (ATEs) and Notes [5][6].
  • The Notes can change how the entry applies. For example, under Note J the carcinogen or mutagen classification does not apply if the substance is shown to contain less than 0.1% w/w benzene; Title II self-classification is then required for those hazard classes [7].
  • Where Table 3 gives no M-factor, the supplier sets its own from the available data [7].

Harmonised classification vs self-classification

  • A harmonised classification is legally binding on every supplier for the hazards it covers.
  • Self-classifications are what companies classify themselves under Title II and notify to ECHA's C&L Inventory (Article 40). They can differ between notifiers.

Approach: I read Articles 4, 36, 37 and 38 and Annex VI of the current consolidated CLP text (consolidated version dated 1 July 2026).

If you give me a substance name or CAS number, I can pull its Annex VI entry, the RAC opinion behind it and any pending CLH proposal.

Q.02

How do I find the entry for my substance?

Search Annex VI Part 3 (Table 3) using an exact identifier: the EC number first, then the CAS number, then the CLP Index number if you have it. Only fall back to a name search if you have none of these. If nothing matches, check whether your substance falls under a group entry. Also check the CLH intentions registry, because an entry can be changed by a pending proposal.

1. Search by identifier, not by name

  • EC number (format XXX-XXX-X). This is the "official number of the substance within the European Union". Annex VI notes it is often more accurate than the CAS number, because one EINECS number covers both the anhydrous and hydrated forms [8].
  • CAS number. Table 3 gives the CAS number for the anhydrous form only. If you search with the CAS number of a hydrate, you may miss the entry [8].
  • Index number (ABC-RST-VW-Y). This is the entry's own reference. ABC is the atomic number of the most characteristic element, or the most characteristic organic group; RST is the substance's sequence number in that series; VW is the form in which it is placed on the market; Y is a check digit [8].
  • Name. Entries use IUPAC names, or the EINECS/ELINCS/NLP names. Active substances in plant protection products and biocides use ISO names. Trade names and common synonyms often won't match [8].

2. If there's no individual entry, check group entries

  • A group entry (for example, a family of salts or compounds) applies to every substance its description covers [9].
  • Group entries with more than four substances usually carry no EC or CAS number, so an identifier search will not find them. Search by the element or chemical family instead [9].
  • If your substance falls under two group entries, you must apply both classifications. Where they conflict on the same hazard, "the most severe classification shall be applied" [9].
  • A group entry marked "except those specified elsewhere in this Annex" means some substances in the group have their own specific entries [9].
  • Entries for salts cover both anhydrous and hydrous forms unless the entry says otherwise [9].

3. Check the entry fits your substance

  • Purity. If an entry is defined at a stated purity, a substance with a higher active content is not covered by that entry and may need its own classification [8].
  • Impurities. If the name includes "(containing ≥ xx % impurity)", that wording is part of the name and must be included on the label [9].
  • Specific concentration limits (SCLs) and harmonised ATEs. If the entry gives these, you must use them when classifying mixtures that contain the substance [10].

Worked example: benzene (CAS 71-43-2) Searching by CAS number returns EC 200-753-7, Index No 601-020-00-8. The entry is classified Flam. Liq. 2 (H225), Carc. 1A (H350), Muta. 1B (H340), STOT RE 1 (H372), Asp. Tox. 1 (H304), Skin Irrit. 2 (H315) and Eye Irrit. 2 (H319). It appears in the original CLP listing and again in ATP10 [11][12][13][14][15][16][17]. The Registry of CLH intentions has no record of a pending proposal for benzene.

4. Then look at the related records

  • Registry of CLH intentions: shows any proposal under way that would add to or revise the entry.
  • RAC opinion: gives the scientific reasons for each hazard class in the entry.
  • C&L Inventory: shows how companies have self-classified the hazards the entry does not cover. You must still self-classify those hazards under Title II.

Approach: I read Annex VI Part 1 of the consolidated CLP text (version of 1 July 2026). I ran the benzene example through Annex VI Table 3 and the ECHA Registry of CLH intentions.

If you send me your substance's name, EC number or CAS number, I'll run all four checks for it now.

Q.03

How does the harmonised classification process work?

Harmonised classification is a five-stage procedure under Article 37 of CLP. First someone notifies ECHA that they intend to propose a classification. They then submit a CLH dossier, the dossier goes to consultation, the Committee for Risk Assessment (RAC) gives its opinion within 18 months, and finally the Commission adopts a delegated act (an ATP) that adds or changes the entry in Annex VI, Part 3, Table 3 [3][4]. Once the entry is in Table 3, every supplier "shall" classify the substance according to it for the hazards it covers [1].

Step 0: Is the substance in scope? (Article 36)

  • Normally harmonised: substances meeting the Annex I criteria for any of these:
    • respiratory sensitisation Cat. 1/1A/1B
    • germ cell mutagenicity, carcinogenicity or reproductive toxicity Cat. 1A/1B/2
    • endocrine disruption (human health or environment) Cat. 1/2
    • PBT, vPvB, PMT or vPvM [2]
  • Always harmonised: active substances under the plant protection products regulation (1107/2009) and the biocidal products regulation (528/2012). For these, only Article 37(1), (4), (5) and (6) apply. That means the routes for manufacturers, importers and downstream users to propose (paragraphs 2 and 3) are not listed for them [2].
  • Other hazard classes: these "may" be harmonised case by case, if the dossier justifies why action is needed at EU level [2].

Step 1: Who prepares the proposal (Article 37(1), (1a), (1b), (2), (3))

  • A Member State competent authority "may" propose a new classification or a revision of an existing one, including SCLs, M-factors or ATEs.
  • The Commission "may" ask ECHA or EFSA to prepare a proposal.
  • These proposals "shall" follow the format in Annex VI Part 2 and contain the information in Annex VI Part 1 [3].
  • Grouping: where it is scientifically justified and possible, proposals "shall aim to prioritise groups of substances" rather than single substances. A group "shall" rest on clear scientific reasoning that lets the properties of its members be predicted reliably [3][18].
  • ECHA and EFSA may advise, on their own initiative, that a harmonised classification would be appropriate [3].
  • Manufacturers, importers and downstream users "may" propose a classification only where Annex VI Part 3 has no entry for that hazard class or differentiation. Their dossier follows REACH Annex I and the CSR Part B format.
  • Fee: if an industry proposal concerns an Article 36(3) (case-by-case) hazard class, it must come with a fee [3].

Step 2: Notify the intention (Article 37(2a))

  • Before submitting, the proposer "shall" notify ECHA of its intention. Within one week, ECHA publishes:
    • the substance name and its EC and CAS numbers
    • the status of the proposal
    • the submitter's name
  • ECHA updates the status after each stage. This is the Registry of CLH intentions [3].

Step 3: Submission, consultation and RAC opinion (Article 37(4))

  • RAC "shall adopt an opinion within 18 months" of receiving the proposal, giving the parties concerned the chance to comment. ECHA then sends the opinion and the comments to the Commission [4].
  • The opinion "shall at least specify":
    • the substance identity
    • the classification, with a statement of reasons
    • SCLs, M-factors or ATEs, where applicable
    • the label elements and supplemental hazard statements
    • any parameters needed to assess mixtures, or substances that contain it as an impurity, additive or constituent [6]

Step 4: Commission decision and ATP (Article 37(5))

  • If the Commission finds harmonisation appropriate, it "shall adopt without undue delay" a delegated act under Article 53a that amends Annex VI Table 3. It should do this preferably before the end of the calendar year after RAC publishes its opinion.
  • Where "imperative grounds of urgency" require it, the urgency procedure in Article 53b applies [4].

Step 5: Keeping entries up to date (Article 37(6))

  • Manufacturers, importers and downstream users who have new information that may change an existing entry "shall submit a proposal". They send it to the competent authority of a Member State where the substance is on the market.
  • That authority notifies ECHA whether it accepts or refuses the proposal and why [3][4].

Shortcut for ED, PBT and vPvB (Article 37(7))

  • To avoid assessing the same hazards twice, the Commission is empowered to add substances directly to Table 3 by delegated act as ED HH 1, ED ENV 1, PBT or vPvB, without a separate CLH dossier. This covers substances that by 11 June 2025 were already on the REACH Candidate List or identified as having those properties under the plant protection or biocides regulations, with a decision adopted under those regulations [4].
  • A second route covers substances where:
    • they were placed on the Candidate List before 11 June 2026 with an Annex XV dossier under assessment by 11 June 2025; or
    • an approval or renewal decision is adopted before 11 June 2032 (plant protection) or 11 June 2030 (biocides), with conditions on whether the application or assessment was submitted by 11 June 2025 [18].

How the stages look in the Registry of CLH intentions The registry tracks each case through these stages: CLH intention, then proposal first submission, then proposal final submission, then start of consultation, then targeted consultation, then final RAC opinion. Two cases show this:

CaseSubmitterTimelineOutcome
Silanamine hydrolysis products with silica (EC 272-697-1), biocidal activeFranceIntention 03-Mar-2017; first submission 06-Dec-2017; final submission 17-Dec-2018; consultation 04-Mar-2019; RAC opinion 05-Dec-2019; targeted consultation 03-Feb-2020Closed; adopted into CLP by Regulation (EU) 2022/692 (STOT RE 2, H373 proposed) [19]
Group of mono- and di-ortho-phthalate esters (C4-C6, benzyl, cyclopentyl/cyclohexyl moieties), REACH-registeredFranceIntention 24-Oct-2023; first submission 07-Apr-2025; final submission 19-Dec-2025; consultation 26-Jan-2026; targeted consultation 24-Aug-2026Ongoing; RAC opinion pending (Repr. 1B H360D, ED HH 1, ED ENV 1 proposed) [20]

The silanamine case took about two years and nine months from intention to RAC opinion, and about five years to adoption.

Approach: I read Articles 4 and 36 to 38 of the consolidated CLP Regulation (version of 1 July 2026) and two cases from ECHA's Registry of CLH intentions. The dates on which an adopted ATP starts to apply are set in each amending regulation; I did not cover them here.

If you give me a substance, I can show where it stands in this process and the RAC opinion behind it.

Q.04