This regulation establishes an exemption from the requirement of a tolerance for residues of isobutane (CAS Reg. No. 75-28-5) when used as an inert ingredient (propellant) in pesticide formulations applied to growing crops and raw agricultural commodities after harvest, and when used as an inert ingredient (propellant) in pesticide formulations applied to animals (used for food). Landis International, on behalf of Whitmire Micro-Gen, submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting establishment of an exemption from the requirement of a tolerance. This regulation eliminates the need to establish a maximum permissible level for residues of isobutane.