"The WHO Recommended Classification of Pesticides by Hazard was approved by the 28th World Health Assembly in 1975 and has since gained wide acceptance. When it was published in the WHO Chronicle, 29, 397-401 (1975), an annex, which was not part of the Classification, illustrated its use by listing examples of classification of some pesticidal active ingredients and their formulations. Later suggestions were made by Member States and pesticide registration authorities that further guidance should be given on the classification of individual pesticides. Guidelines were first issued in 1978, and have since been revised and reissued every few years. Up until the present revision the original guidelines approved by the World Health Assembly in 1975 have been followed without amendment. In December, 2002 the United Nations Committee of Experts on the Transport of Dangerous Goods and on the Globally Harmonized System of Classification and Labelling of Chemicals (UNCETDG/GHS) approved a document called 'The Globally Harmonized System of Classification and Labelling of Chemicals' with the intent to provide a globally-harmonized system1 (GHS) to address classification of chemicals, labels, and safety data sheets. The GHS (with subsequent revisions) is now being widely used for the classification and labeling of chemicals worldwide. For this revision of the Classification the WHO Hazard Classes have been aligned in an appropriate way with the GHS Acute Toxicity Hazard Categories for acute oral or dermal toxicity as the starting point for allocating pesticides to a WHO Hazard Class (with adjustments for individual pesticides where required). It is anticipated that few of the more toxic pesticides will change WHO Hazard Class as a result of this change. As has always been the case, the classification of some pesticides has been adjusted to take account of severe hazards to health other than acute toxicity (as described in Part II). The GHS Acute Toxicity Hazard Category for each pesticide is now presented alongside the existing information"--Page 1.