OBJECTIVES The objective of this study was to evaluate the development toxicity (including teratogenicity) of maternally in haled commercial hexane vapor in the pregnant CD?-1 mouse. The potential of the test chemical to produce maternal toxicity was also determined. This study was perfomed in responcse to the EPA Final Test Rule on commercial hexane ( EPA@ 1988a ) and in accordance with EPA testing standards (EPA@ 1983; EPA@ 1986) .