This rule extends a time-limited tolerance for residues of the insecticide tebufenozide and its metabolites in or on leafy vegetables (Crop Group 4) and brassica leafy vegetables (Crop Group 5) at 5.0 parts per million (ppm) for an additional 18-month period, to August 31, 2000. This action is in response to EPA's granting of an emergency exemption under section 18 of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) authorizing use of the pesticide on leafy vegetables (Crop Group 4) and brassica leafy vegetables (Crop Group 5). Section 408(l)(6) of the Federal Food, Drug, and Cosmetic Act (FFDCA) requires EPA to establish a time-limited tolerance or exemption from the requirement of a tolerance for pesticide chemical residues in food that will result from the use of a pesticide under an emergency exemption granted by EPA under section 18 of FIFRA.