While there may be several legislations about grouping substances globally, this section focuses on the use of grouping in EU legislation. In the EU, the European Chemical Agency (ECHA) coordinates the REACH regulation for the restriction, evaluation and authorization of substances based on hazard classifications and the CLP regulation for labelling based on hazard classifications. REACH Annex XI section 1.5 specifies how groups or categories of substances can be defined and which regulatory actions can be applied . It states that "substances whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity may be considered as a group, or 'category' of substances" . The toxicological or hazard properties referred to are described in the CLP regulation shown in Under REACH, UVCBs are regulated based on the structural similarity of the constituents identified and can also be regulated as part of a different group. This means that certain components of these substances may be identified and registered as part of a different group.