This regulation establishes an increase in tolerances for the sum of the residues of imazethapyr and its metabolites, CL 288511, (2- [4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-(1- hydroxyethyl)-3-pyridine carboxylic acid), and CL 182704, (5-[1-(beta- D-glucopyranosyloxy)ethyl]-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5- oxo-1H-imidazol-2-yl]-3-pyridinecarboxylic acid), applied as its acid or ammonium salt in or on rice grain at 0.3 ppm, rice straw at 0.4 ppm, and imazethapyr and its metabolite, CL 288511 in or on crayfish at 0.15 ppm. BASF Corporation requested the tolerances for rice grain and rice straw under the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act of 1996 (FQPA), because of a requested increase in the use rate of imazethapyr in rice. In addition, this regulation increases the tolerance on crayfish from 0.10 ppm to 0.15 ppm due to exposure of crayfish raised in rice fields to imazethapyr.