About published non-CLP classifications
Non-CLP classifications are usually published in supplier Safety Data Sheets (SDSs), such as GHS SDSs, which are likely to be easy to convert to CLP. Other information includes old CHIP SDSs, or non-EU SDSs from other jurisdictions such as the USA or Canada before they adopted GHS. There can also be information on old supply labels, or on Transport labels.
Sometimes it can be possible to convert these non-CLP classifications into CLP classifications, avoiding the need for further tests being carried out, at least for some hazards:
However, it can be more accurate to use data from a non-GHS Safety Data Sheet to classify the hazards from first principles, see https://ttenvironmenta.wpengine.com/clp-knowledgebase/using-data-from-non-clp-safety-data-sheets/ and https://ttenvironmenta.wpengine.com/knowledgebase_category/first-principles-clp-classification/ .