Update to RIFM fragrance ingredient safety assessment, 2-acetylthiazole, CAS Registry Number 24295-03-2

2-Acetylthiazole was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, photoirritation/photoallergenicity, skin sensitization, and environmental safety. Target data show that 2-acetylthiazole is not genotoxic. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the Threshold of Toxicological Concern (TTC) for a Cramer Class II material, and the exposure to 2-acetylthiazole is below the TTC (0.009 mg/kg/day, 0.009 mg/kg/day, and 0.47 mg/day, respectively). The skin sensitization endpoint was completed using the Dermal Sensitization Threshold (DST) for reactive materials (64 μg/cm²); exposure is below the DST. The photoirritation/photoallergenicity endpoints were evaluated based on ultraviolet/visible (UV/Vis) spectra; 2-acetylthiazole is not expected to be photoirritating/photoallergenic. The environmental endpoints were evaluated; 2-acetylthiazole was found not to be Persistent, Bioaccumulative, and Toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards, and its risk quotients (RQs), based on its current volume of use (VoU) in Europe (EU), North America (NA), Asia-Pacific (AP), Japan (JP), and South America (SA) (i.e., Predicted Environmental Concentration/Predicted No Effect Concentration [PEC/PNEC]), are <1.