Prenatal developmental toxicity study of ethyl tertiary-butyl ether in rats

Ethyl tertiary-butyl ether (ETBE) is commonly used as an oxygenated gasoline additive. In this study, we evaluated its developmental toxicity in rats. ETBE was administered by gavage to 21 or 22 pregnant female Sprague-Dawley rats per group at dose levels of 0, 100, 300 and 1000 mg/kg/day from days 5 through 19 postcoitum to assess its effects on pregnant animals and their embryos and fetuses applied to the OECD testing guideline (no. 414) correspondingly. There were no toxicological effects attributable to ETBE regarding clinical signs, body weight, food intake, necropsy or examination at caesarean section in pregnant animals. There were also no toxicological effects on external, visceral and skeletal examinations of embryos and fetuses. These results indicate that, under the conditions of this study, ETBE had no toxicological effects on pregnant rats or their embryos and fetuses and that the no observed adverse effect level was 1000 mg/kg/day both for pregnant rats and their embryos and fetuses.