This rule establishes tolerances for the sum of the residues of the herbicide imazethapyr, 2-[4,5-dihydro-4-methy1-4-(1- methylethyl)-5-oxo-1H-imidazo1-2-yl]-5-ethy1-3-pyridine carboxylic acid, as its ammonium salt and its metabolite, 2-[4,5-dihydro-4-methyl- 4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-(1-hydroxyethyl)-3-pyridine carboxylic acid, both free and conjugated, in or on [[Page 4092]] alfalfa, forage and hay at 3.0 parts per million (ppm). The American Cyanamid Co. requested this regulation that establishes the maximum permissible level for residues of the herbicide in or on alfalfa.