Pentoxazone (Second Edition) (Pesticides)

Food Safety Commission of Japan (FSCJ) conducted a risk assessment of pentoxazone (CAS No. 110956-75-7), an oxazolidine herbicide, based on submitted documents. A request for reevaluation was made under the Agricultural Chemical Regulation Act. Additional information was submitted by the Ministry of Agriculture, Forestry and Fisheries, which included data on fate in livestock (goats and chickens), genotoxicity, and related published scientific literatures. Major adverse effects of pentoxazone were observed in the liver (hepatocellular hypertrophy) and urinary bladder (proliferative lesions including mucosal epithelial hyperplasia). Adverse effects were observed on neither fertility, teratogenicity, nor biologically significant genotoxicity. The lowest no-observed-adverse-effect level (NOAEL) obtained from these studies was 23.1 mg/kg bw per day in the one-year chronic toxicity study in dogs. FSCJ specified an acceptable daily intake (ADI) of 0.23 mg/kg bw per day by applying a safety factor of 100 to this NOAEL.