Two-generation reproduction study on commercial hexane solvent

The reproductive effects of inhalation exposure to commercial hexane vapors were evaluated in Sprague-Dawley rats. Males and females were exposed to commercial hexane vapor at target concentrations of 0, 900, 3000 or 9000 ppm for 6 h a day, 5 or 7 days a week, over two generations. In addition to pre-breed exposures of 10 weeks' duration, exposures continued through mating, gestation and lactation. At both the F0 breed to produce F1 litters and the F1 breed to produce F2 litters, reproductive parameters were unaffected by commercial hexane exposure. The mating, fertility and gestational indices, as well as litter size and postnatal survival, were not significantly different between exposure groups. However, reductions in body weight and body weight gain were observed in both F1 and F2 litters exposed to 9000 ppm. Effects on body weight were not observed in offspring exposed to the two lower concentrations of commercial hexane. Histopathological examination of selected tissues revealed hyaline droplet nephropathy in adult F0 and F1 males exposed to 9000 ppm. This finding was anticipated and is not believed to be relevant for the assessment of human health effects. No other treatment-related histopathological lesions were observed. Thus, exposure of rats to commercial hexane for two generations resulted in reduced body weight gains at 9000 ppm but no adverse effects on reproduction. These findings suggest that occupational exposure to commercial hexane vapors at currently recommended threshold limit value concentrations (i.e. TLV for n-hexane is 50 ppm and TLV for other hexane isomers is 500 ppm) should not pose a reproductive hazard.