If you sell or distribute chemicals (e.g. retailers), your duties may be more limited than those of manufacturers, importers, and downstream users. If you only store and sell on the chemical to third parties (e.g. consumers) then you can rely on the classification and labelling information that has been provided to you by those further up the supply chain (i.e. from the manufacturer or the importer). This is a refinement over the previous system (CHIP), where distributors and retailers etc. chain had the same level of duty to classify as upstream actors.
Distributors etc. should nevertheless ensure that you understand the changes made by CLP.
If you alter the chemical in any way (e.g. re-formulate) before placing it on the market, you will then take on the role of a downstream user and you will be responsible for classifying, labelling and packaging that chemical.
All those in the supply chain are responsible for ensuring that substances and mixtures are labelled and packaged correctly before being placed on the market.