Final Report on the Safety Assessment of Butoxyethanol

Abstract

Butoxyethanol is an ether alcohol used as a solvent in hair and nail products at concentrations up to 10%. This ingredient is absorbed through the skin, metabolized to butoxyacetic acid, and excreted in urine. Acute inhalation toxicity was related to concentration and duration of exposure; pathological changes occur in the kidneys, liver, and lungs. Butoxyethanol was only slightly toxic in an acute oral study in rats and in a dermal study in rabbits. Butoxyethanol was nephrotoxic in an intravenous study in rats, but not when administered intraperitoneally. No evidence of genotoxicity was seen in a battery of tests with metabolic activation, but positive and negative effects were seen in the absence of metabolic activation. A dermal study of a cosmetic product containing 10% Butoxyethanol was not carcinogenic in rats, whereas a rust-preventive product containing 2.5% Butoxyethanol was carcinogenic (90.9% of the rust preventive was a petroleum distillate). There is some evidence for reproductive and developmental toxicity in oral and inhalation studies involving rats, rabbits, and mice, but no such effects in dermal studies in rats. Clinical tests and reports from occupational exposures indicate Butoxyethanol to be an irritant when inhaled. Butoxyethanol was not a sensitizer or photosensitizer in clinical tests. Undiluted Butoxyethanol is recognized to be a severe ocular irritant, but aqueous concentrations of 15 and 5% produced only moderate and no corneal injury, respectively. In consideration of these data, the Cosmetic Ingredient Review Expert Panel concluded that this ingredient may be used safely in hair and nail cosmetic products at concentrations up to 10%.