This regulation establishes a time-limited tolerance for combined residues of diuron in or on catfish. This action is in response to EPA's granting of an emergency exemption under section 18 of the Federal Insecticide, Fungicide, and Rodenticide Act authorizing use of the pesticide in catfish ponds. This regulation establishes a maximum permissible level for residues of diuron in this food commodity pursuant to section 408(l)(6) of the Federal Food, Drug, and Cosmetic Act, as amended by the Food Quality Protection Act of 1996. The tolerance will expire and is revoked on June 30, 2001.