How to read Harmonised Classifications
There are two aspects to reading Harmonised Classifications:
- getting information from the published Harmonised Classification list
- being aware of some of the snags with the published Harmonised Classification list
The good news is that Harmonised Classifications always take the same format, regardless of whether they are published in print, or online as part of the Classification and Labelling (C&L) Inventory, so once you can read them in one format, you can read them in all formats.
Getting information from the published Harmonised Classification list
The published Harmonised classification list can be read as follows:
You can download this infographic as a pdf: Reading Harmonised Classifications v1.3 25-01-2018 .
You should also download the list of notes to the Harmonised Classification list, for completeness: Notes to Harmonised Classifications 10th ATP May 2017.
One of the most important things to remember about Harmonised Classifications is that where there is a single asterisk, this means that a more severe classification can be applied if you have data which indicates this. No asterisk means you should use the classification as it stands. Also, you need to check any Notes carefully, as this can sometimes mean that the Harmonised Classification does not apply in certain circumstances.
Where an Index Number / Harmonised Classification covers several substances
The Index Number can be used to cover different (but chemically similar) substances which have the same Harmonised Classification hazards. This can mean that there are multiple product names, EC numbers and CAS numbers in the same table cell of the published Harmonised Classification List (Table 3 to Annex VI of the CLP Regulation).
To ensure that the correct EC and CAS numbers are assigned to the right chemical, a number is added after the name in square brackets, and the same number is placed after the EC number and CAS number as well. e.g. if there are three substances, the suffix numbers ,  and  will be used.
This infographic can be downloaded as a pdf: single HC mult subs 1.2 .
Snags with the published Harmonised Classification list
There are several potential problems with using the Harmonised Classification list:
- The Harmonised Classification may have changed in a later ATP (this applies to published information in the CLP Regulation itself. Usually the online information is up to date)
- The Harmonised Classification may not be fully up to date for Carcinogens and Mutagens (a problem which has been reported to ECHA by the Environment Agency, having been identified by a UK hazardous waste classification specialist)
- You can have the same CAS number, but different Index Numbers and Harmonised Classifications due to particle size differences (e.g. sodium perborate), or concentration differences (although these are quite rare occurrences).
For more details, see: Things to watch out for with Harmonised Classifications.