To face this danger, and given the reality of the extensive global trade in chemicals and the need to develop national programs to ensure their safe use, transport and disposal, it was recognized that an internationally-harmonized approach to classification and labelling would provide the foundation for such programs. Once countries have consistent and appropriate information on the chemicals they import or produce in their own countries, the infrastructure to control chemical exposures and protect people and the environment can be established in a comprehensive manner.

The new system, which was called "Globally Harmonized System of Classification and Labelling of Chemicals (GHS)", addresses classification of chemicals by types of hazard and proposes harmonized hazard communication elements, including labels and safety data sheets. It aims at ensuring that information on physical hazards and toxicity from chemicals be available in order to enhance the protection of human health and the environment during the handling, transport and use of these chemicals. The GHS also provides a basis for harmonization of rules and regulations on chemicals at national, regional and worldwide level, an important factor also for trade facilitation.

The first edition of the GHS, which was intended to serve as the initial basis for the global implementation of the system, was approved by the Committee of Experts at its first session (11-13 December 2002) and published in 2003. The first revised edition of the GHS (GHS Rev.1) was published in 2005 and included the amendments to the first edition adopted by the Committee of Experts at its second session (10 December 2004). At its third session (14 December 2006), the Committee of Experts adopted a set of amendments to the first revised edition of the GHS, which are included in the second revised edition of the GHS (published in July 2007).

At its fourth session (12 December 2008), the Committee of Experts adopted a set of amendments to the second revised edition of the GHS, which were consolidated in document ST/SG/AC.10/36/Add.3. The third revised edition of the GHS (published in July 2009) takes into account all these amendments which concern, inter alia: new provisions for the allocation of hazard statements and for the labelling of small packagings; two new sub-categories for respiratory and skin sensitization; the revision of the classification criteria for long-term hazards (chronic toxicity) to the aquatic environment; and a new hazard class for substances and mixtures hazardous to the ozone layer.

While governments, regional institutions and international organizations are the primary audiences for the GHS, it also contains sufficient context and guidance for those in industry who will ultimately be implementing the requirements which have been adopted.

The Plan of Implementation of the World Summit on Sustainable Development (WSSD), adopted in Johannesburg in 2002, encourages countries to implement the GHS as soon as possible with a view to having the system fully operational by 2008.

Information about the status of implementation of the GHS by country is available (in English only) in the page following the link "GHS implementation" on the left hand menu.