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Description of key information

Two key 90 day repeat dose inhalation studies were identified for commercial hexane. One study of the test material reported a NOAEC >= 31652 mg/m3 for rats (OECD TG 413) the other reported a NOAEC >= 31652 mg/m3 for mice (OECD TG 413) (API, 1990, Klimisch=1).
One read across study was identified for repeat dose oral (Krasavage, 1980; Klimisch score =2).

Key value for chemical safety assessment

Additional information

In a sub-chronic toxicity study of commercial hexane, groups of 10 male and 10 female rats were exposed to concentrations of 0, 904, 2984, and 8992 ppm of test substance for 6 hrs/day, 5 days/week, for 13 weeks via inhalation route (API, 1990; Klimisch score =1).

There was no mortality among the exposed groups, and no treatment related effects to body weight gain. At sacrifice hemorrhage and inflammation in high dose male livers were considered the only possible treatment related effects. The significance of this effect is uncertain. The NOAEC for male rats in 2984 ppm, and the LOAEC is 8992 ppm (10504 mg/m3). The NOAEC for female rats in 8992 ppm (31652 mg/m3).In a similar sub-chronic toxicity study, groups of 10 male and 10 female mice were exposed to concentrations of 0, 904, 2,984, and 8,992 ppm of test substance for 6 hrs/day, 5 days/week, for 13 weeks (API, 1990; Klimisch score =1). Seven animals died during the study, however, all deaths were accidental and not considered treatment related. The NOAEC for mice is 8992 ppm (31652 mg/m3).

In a key read across repeat dose oral toxicity study (Krasavage, 1980; Klimisch score =2), the effect of oral exposure to n-hexane was examined. 5 male rats were exposed to concentrations of 6.60, 13.2, and 46.2 mmol/kg bw (568, 1135, 3973 mg/kg) by oral gavage for 90 to 120 days. Neurological effects were only seen at the highest dose level after an average of 101.3 days of exposure. The LOAEL for neurological effects is 46.2 mmol/kg bw (37973 mg/kg), and the NOAEL is 13.2 mmol/kg bw (1135 mg/kg). Reduced body weight gain was seen at all three dose levels, however was only considered treatment related in the 13.2 and 46.2 mmol/kg bw groups. The NOAEL is therefore 6.60 mmol/kg bw.

Justification for classification or non-classification

This substance is not classified for repeat dose toxicity.