This regulation establishes an exemption from the requirement of a tolerance for residues of the hygromycin B phosphotransferase (APH4) marker protein on cotton when applied/used as an inert ingredient in plant-incorporated protectants. Syngenta Seeds submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act of 1996 (FQPA), requesting an exemption from the requirement of a tolerance. This regulation eliminates the need to establish a maximum permissible level for residues of hygromycin B phosphotransferase (APH4) marker protein when used as a plant-incorporated protectant formulation inert ingredient.