This regulation establishes tolerances for residues of isoxadifen-ethyl (ethyl 5,5-diphenyl-2-isoxazoline-3-carboxylate; CAS Reg. No. 163520-33-0) and its metabolite 4,5-dihydro-5,5,diphenyl-3- isoxazolecarboxylic acid when used as an inert ingredient (safener) in or on corn, sweet, kernel plus cob with husks removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; corn, pop, stover; and corn, oil. EPA is also revising existing tolerances for residues of isoxadifen-ethyl in or on corn, field, forage and corn, field, hay, and removing the seasonal application rate specification from existing tolerances. Interregional Research Project Number 4 (IR-4) and Bayer CropScience requested certain tolerance amendments for the inert ingredient safener isoxadifen-ethyl under the Federal Food, Drug, and Cosmetic Act (FFDCA).