"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.

The understanding that some pesticides are more hazardous than others is well established. Recognition of this is reflected by the World Health Organization (WHO) Recommended Classification of Pesticides by Hazard, which was first published in 1975. The document classifies pesticides in one of five hazard classes according to their acute toxicity. In 2002, the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) was introduced, which in addition to acute toxicity also provides classification of chemicals according to their chronic health hazards and environmental hazards.

The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) addresses classification and labelling of chemicals by types of hazards. It provides the basis for worldwide harmonization of rules and regulations on chemicals and aims at enhancing the protection of human health and the environment during their handling, transport and use by ensuring that the information about their physical, health and environmental hazards is available. The sixth revised edition includes, inter alia, a new hazard class for desensitized explosives and a new hazard category for pyrophoric gases; miscellaneous amendments intended to further clarify the criteria for some hazard classes (explosives, specific target organ toxicity following single exposure, aspiration hazard, and hazardous to the aquatic environment) and to complement the information to be included in section 9 of the Safety Data Sheet; revised and further rationalized precautionary statements; and an example of labelling of a small packaging in Annex 7.

Concern about health effects from exposure to pesticides in foods is growing as scientists learn more about the toxic properties of pesticides. The Delaney Clause, a provision of the Food, Drug and Cosmetic Act, prohibits tolerances for any pesticide that causes cancer in test animals or in humans if the pesticide concentrates in processed food or feeds. This volume examines the impacts of the Delaney Clause on agricultural innovation and on the public's dietary exposure to potentially carcinogenic pesticide residues. Four regulatory scenarios are described to illustrate the effects of varying approaches to managing oncogenic pesticide residues in food.