This European Standard specifies requirements for the maximum amount and, in some cases, the maximum concentration of certain substances and mixtures used in experimental sets for chemistry and related activities.These substances and mixtures are:-those classified as dangerous by the EC-legislation applying to dangerous substances [1], [2] and dangerous mixtures [2], [3];-substances and mixtures which in excessive amounts could harm the health of the children using them and which are not classified as dangerous by the above mentioned legislation; and-any other chemical substance(s) and mixture(s) delivered with the experimental set.This standard applies to experimental sets for chemistry and related activities including crystal growing sets, carbon dioxide generating experimental sets and supplementary sets. It also covers sets for chemical experiments within the fields of mineralogy, biology, physics, microscopy and environmental science whenever they contain one or more chemical substances and/or mixtures which are classified as hazardous according to Regulation (EC) No. 1272/2008/EC [2]. This standard also specifies requirements for marking, a contents list, instructions for use, eye protection and for the equipment intended for carrying out the experiments.This standard does not apply to toys that are covered by EN 71-13 (e.g. cosmetic kits). Requirements for certain other chemical toys are given in EN 71-5.NOTEThe terms "substance" and "preparation", as used in Directives 67/548/EEC [1] and 1999/45/EC [3], are also used in the "REACH Regulation", Regulation (EC) No. 1907/2006 [4]. According to the Globally Harmonised System (GHS) of classification and labelling of chemicals, which in the European Union has been enacted by Regulation (EC) No. 1272/2008 (classification, labelling and packaging of substances and mixtures) [2], the timetable for the introduction of GHS has to be followed.The words "preparation" and "mixture" should be considered synonymous; both are a mixture or solution of substances that do not react with each other. The old term "preparation" will be replaced by the new term "mixture" in due course. In this standard, only the term "mixture" is used.