These guidelines supersede the earlier product chemistry guidelines published as Subdivision D of the Pesticide Assessment Guidelines (PB83-153890) and provide harmonization, where possible, with similar guidelines published by the Organization for Economic Cooperation and Development (OECD). In the revised guidelines, Series 60 is replaced by this guideline, OPPTS 830.1000. Series 61 and 62 are combined in one group titled 'Group A--Product Identity, Composition, and Analysis.' Physical and chemical characteristics remains a separate section, titled 'Group B--Physical/Chemical Properties.' in the new guidelines. The single Series 64 guideline, 64--1 Submittal of Samples, has been placed in Group A as OPPTS 830.1900. Table 1 provides a listing of the OPPTS test guidelines and shows the correlation between the guideline numbers from Subdivision D and the new guideline numbers.