This regulation establishes a tolerance for residues of pyrithiobac sodium (sodium 2-chloro-6-[(4,6-dimethoxypyrimidin-2- yl)thio]benzoate) in or on cotton, undelinted seed and cotton gin byproducts. DuPont Agricultural Products, Wilmington, DE requested this tolerance under the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act (FQPA) of 1996.