4‐tert‐Octylphenol

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated the developmental toxicity of 4‐tert‐octylphenol. In 2015, the maximum concentration at the workplace (MAK value) for 4‐tert‐octylphenol was set at 0.5 ml /m3 (4.3 mg/m3). In a screening study in rats with gavage administration, litter size and body weight of the progeny at postnatal day 4 was reduced at 500 mg/kg body weight and day, accompanied by maternal toxicity. A NOAEL for foetotoxicity of 250 mg/kg body weight and day was derived, corresponding to a concentration of 28.5 ml/m3 at the workplace. In a 2‐generation feeding study in rats, foetotoxicity was not observed until postnatal day 13. At 111–369 mg/kg body weight and day, vaginal opening or preputial separation of the F2 progeny was delayed. A NOAEL of 10.9–32.6 mg/kg body weight and day was derived for postnatal developmental toxicity in rats, corresponding to 1.2–3.7 ml/m3. Because adequate studies of prenatal developmental toxicity over the complete period of organogenesis are lacking, data are not sufficient for classification and 4‐tert‐octylphenol is assigned to Pregnancy Risk Group D. Completed: October 7, 2015