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.