(18)To ensure that customers receive information on hazards, suppliers of substances and mixtures should ensure that they are labelled and packaged in accordance with this Regulation before placing them on the market, according to the classification derived. In fulfilling their responsibilities downstream users should be allowed to use the classification of a substance or mixture derived in accordance with this Regulation by an actor in the supply chain, provided that they do not change the composition of the substance or mixture, and distributors should be allowed to use the classification of a substance or mixture derived in accordance with this Regulation by an actor in the supply chain.