This rule extends a time-limited tolerance for residues of the herbicide primisulfuron-methyl and its metabolites in or on bluegrass hay at 0.1 part per million (ppm) for an additional 18-month period, to April 30, 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 bluegrass grown for seed. 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 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 section 18 of FIFRA.