GHS stands for Globally Harmonized System of Classification and Labelling of Chemicals. It is issued and actualised by the UN and may be taken over by the respective lawmakers – completely, partly or with extensions – into their national or regional legislation.
The EU did this by the Regulation (EC) No 1272/2008 of 16 December 2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006.
In Principle all parts of this EU-GHS or CLP (Classification, Labelling and Packaging) called regulation may already be applied, because it is immediately effective in all member states. For substances its application is already mandatory. For mixtures (=preparations) this will be the case as of 1 June 2015. Manufacturers of mixtures should care about getting classification-relevant substance data (e.g. provided by their raw material suppliers), since otherwise they have to classify their products too “conservatively”.
In the EU the prescriptions for the compilation of Safety Data Sheets are fixed in Annex II of the Regulation (EC) No 1907/2006 (REACH), which in turn has been adapted to the GHS resp. CLP by Regulation (EU) No 453/2010.