RIFM fragrance ingredient safety assessment, 4-isopropylphenol, CAS Registry Number 99-89-8

Abstract

4-Isopropylphenol was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, photoirritation/photoallergenicity, skin sensitization, and environmental safety. Data from read-across analog p-cresol (CAS # 106-44-5) show that 4-isopropylphenol is not expected to be genotoxic. Data on read-across analog p-cresol (CAS # 106-44-5) provide a calculated Margin of Exposure (MOE) > 100 for the repeated dose toxicity and reproductive toxicity endpoints. Data from read-across analog thymol (CAS # 89-83-8) show that there are no safety concerns for 4-isopropylphenol for skin sensitization under the current declared levels of use. The photoirritation/photoallergenicity endpoints were evaluated based on ultraviolet/visible (UV/Vis) spectra; 4-isopropylphenol is not expected to be photoirritating/photoallergenic. The local respiratory toxicity endpoint was evaluated using the Threshold of Toxicological Concern (TTC) for a Cramer Class I material, and the exposure to 4-isopropylphenol is below the TTC (1.4 mg/day). The environmental endpoints were evaluated; 4-isopropylphenol was found not to be Persistent, Bioaccumulative, and Toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards, and its risk quotients, based on its current volume of use (VoU) in Europe and North America (i.e., Predicted Environmental Concentration/Predicted No Effect Concentration [PEC/PNEC]), are <1.