This regulation extends a time-limited tolerance for residues of phosphine resulting from the use of the rodenticide zinc phosphide in or on timothy, alfalfa, and clover at 0.1 part per million (ppm) for an additional 1\1/2\ -year period. This tolerance will expire and is revoked on August 1, 2001. 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 timothy, alfalfa, and clover. Section 408(l)(6) of the Federal Food, Drug, and Cosmetic Act requires EPA to establish a time-limited tolerance or exemption from the requirement for 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 FIFRA section 18.