For most substances, classification under CLP is the supplier’s own judgement. For a few thousand, it is not: the European Union has decided the classification, published it in Annex VI to the CLP Regulation, and made it binding. Knowing which of the two you are looking at changes what the document means.
Self-classification and harmonised classification
Regulation (EC) No 1272/2008 — CLP — requires a supplier to classify a substance before placing it on the market. In the ordinary case the supplier evaluates the available information against the criteria and reaches a conclusion. Two suppliers with the same substance and different data can reach different conclusions, and both can be acting properly.
Harmonised classification removes that discretion for specified hazard classes. Where Annex VI carries an entry, the classification in that entry is binding across the Union. A supplier may classify for hazard classes the entry does not cover, and may classify more severely where its own data support it, but it may not classify below the harmonised entry for the classes the entry addresses.
This is why a document should say which of the two it is showing. “Classified as a category 1B carcinogen” means something different when it is one supplier’s reading of the literature and when it is a binding entry agreed at Union level.
The index number
Each Annex VI entry carries an index number in the form 601-020-00-8: four groups, unlike a CAS number’s three.
The first group indicates the element or organic class the entry is filed under — 601 is hydrocarbons, 603 alcohols and ethers, 607 organic acids, and so on. The remaining groups position the entry within that group and close with a check digit.
The index number is not interchangeable with the CAS number and does not replace it. A single Annex VI entry can cover a group of substances, and some entries are written with a concentration in the name, such as sulphuric acid ... %. That ellipsis is part of the official entry name, not a gap in the document.
What an entry contains
- The index number and the international chemical identification
- EC number and CAS number where they exist
- Hazard class and category codes, such as
Carc. 1AorFlam. Liq. 2 - Hazard statement codes, such as
H350orH225 - Pictogram and signal word codes
- Specific concentration limits, M-factors and acute toxicity estimates, where they have been set
- Notes, which can materially change how the entry applies
Adaptations to technical progress
Annex VI is amended regularly by Adaptations to Technical Progress — ATPs. An ATP can add an entry, change a classification, or tighten a concentration limit. Each has a date from which it applies.
The practical consequence is that a safety data sheet has a shelf life that nobody prints on it. A document correct against one ATP can be out of date against the next, and the only way to tell is to know which version of the annex it was read against. A document that does not record that version cannot be checked.
Every classification MolGod shows names the adaptation it was read against, so the statement can be tested rather than trusted.
When there is no entry
Most substances have no harmonised entry. Their absence from Annex VI is not a finding of safety — it means the Union has not taken a position, usually because no dossier has come forward, not because a hazard was ruled out.
This is the point at which documentation most often goes wrong. Writing “not classified” where the correct statement is “no harmonised entry exists; classification rests on the supplier’s evaluation” turns a gap in the record into an apparent clearance. On MolGod the absence of an entry is stated as an absence.
Checking a classification yourself
- Find the substance’s index number if it has one. No index number means no harmonised entry.
- Read the hazard class and category codes, not the prose.
Carc. 1Bis precise; “may cause cancer” is a translation of it. - Check for specific concentration limits and M-factors — they change the outcome for mixtures.
- Read the notes on the entry.
- Confirm which ATP the reading was made against.
On any MolGod substance page these five things are on the page itself, with the index number stated and the adaptation named. Search the catalogue by CAS number to see one.
Legal basis: Regulation (EC) No 1272/2008 (CLP), Annex VI, as amended by successive Adaptations to Technical Progress. The authoritative text is the consolidated regulation published by the European Union; this page is an explanation of it, not a substitute for reading it.