1,2:3,4-Diepoxybutane in blood of male B6C3F1 mice and male Sprague-Dawley rats exposed to 1,3-butadiene

► 1,2:3,4-Diepoxybutane (DEB) is the most genotoxic metabolite of 1,3-butadiene (BD). ► DEB blood levels were determined in rodents at BD concentrations down to 1 ppm. ► DEB blood levels in mice increased from 5 nM at 1 ppm BD to 1860 nM at 1250 ppm. ► DEB levels in rats were 1 nM at 1 ppm BD and reached a plateau of 100 nM at 200 ppm. ► The data explain why the tumorigenic potency of BD is low in rats compared to mice.