Butan-2-ol

Endpoint summary

Description of key information

Secondary butanol is reported to have low acute oral toxicity following oral adminstration. Reported oral LD50s of secondary butanol were 2054 mg/kg body weight for males and 2328 mg/kg body weight for females in a study performed similar to test guidelines and in compliance with good laboratory practice  (Gill, 1991). The calculated oral LD50 in rats was 2193 mg/kg body weight. Clinical signs included gait and/or posture abnormalities in all rats at all dose levels. In the higher dose groups some rats were comatose or prostrate within a few hours of dosing, with some animals being unconscious for 24 hours or more.
Secondary butanol is of low acute dermal toxicity. The dermal LD50 value for secondary butanol is greater than 2000 mg/kg body weight in rats in a study performed similar to test guidelines and in complaince with good laboratory practice (Price, 1986). None of the rats died over the observation period, and all rats gained weight relative to their day 1 body weights by the end of the 14-day observation period, with no signs of toxicity. 
 In accordance with column 2 of REACH Annex VIII, the acute toxicity by inhalation study (required in section 8.5.2) does not need to be conducted as acute toxicity studies are available for the oral and dermal routes of exposure.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 193 mg/kg bw

Additional information

Acute Toxicity: Oral

The potential acute oral toxicity study of secondary butanol was assessed in Fischer 344 rats in a study similar in methodology to OECD Guidelines for the Testing of Chemicals No. 403 and in compliance with Good Laboratory Practice (Gill, 1991). Groups of 5 males and 5 females were administered undiluted test article via gavage at dose levels of 950, 1200, 1500, 2000, or 2400 mg/kg body weight. Rats were observed for clinical signs over a 14 day observation period and body weights were measured on days 1, 7, and 14. No animals died in the 950 mg/kg body weight group, one animal died in each of the 1200 and 2000 mg/kg body weight groups, two animals died in the 1500 mg/kg body weight group, and eight animals died in the 2400 mg/kg body weight group. All rats at all dose levels had gait and/or posture abnormalities. In the higher dose groups, some rats were comatose or prostrate within a few hours of dosing, with some animals being unconscious for 24 hours or more. All animals had either died or recovered by day 3. All surviving rats had gained weight relative to their body weights by the end of the 14 day observation period. The LD50 for males was calculated to be 2054 mg/kg body weight with 95% confidence intervals of 1283 to 4018 mg/kg body weight. For females, the LD50 was calculated to be 2328 mg/kg body weight with 95% confidence intervals of 1470 to 5428 mg/kg body weight. Finally, the oral LD50 of secondary butanol for males and females was calculated to be 2193 mg/kg body weight with 95% confidence intervals of 1608 to 4146 mg/kg body weight.

Secondary butanol was not classified as acutely toxic following oral exposure according to CLP.

Acute Toxicity: Dermal

The potential acute dermal toxicity study of secondary butanol was assessed in Fischer 344 rats in a study similar in methodology to OECD Guidelines for the Testing of Chemicals No. 402 and in compliance with Good Laboratory Practice (Price, 1986). Five male and 5 female rats were administered 2000 mg/kg body weight of the undiluted test article with an occlusive wrapping to the dorsal part of the animals for 24 hours. At the end of the exposure period, the tape and foil were carefully removed and the skin was washed with warm dilute detergent solution and dried. The animals were observed for signs of toxicity for 14 days after dosing. Body weights were recorded on Days 1, 7, and 14. None of the rats died over the observation period, and all rats gained weight relative to their day 1 body weights by the end of the 14-day observation period. In addition, no clinical signs of toxicity were observed. The acute dermal LD50 of the undiluted test material in rats was greater than 2000 mg/kg body weight.

Secondary butanol was not classified as acutely toxic following dermal exposure according to CLP.

Acute Toxicity: Inhalation

In accordance with column 2 of REACH Annex VIII, the acute toxicity by inhalation study (required in section 8.5.2) does not need to be conducted as acute toxicity studies are available for the oral and dermal routes of exposure.

Justification for classification or non-classification

Acute toxicity: The substance does not meet the criteria for classification and labelling for this endpoint, as set out in Regulation (EC) No. 1272/2008.

Specific organ toxicity, Neurotoxicity: According to CLP classification criteria, the substance does meet the criteria for classification and labelling for this endpoint (STOT single exposure category 3, H336 - May cause drowsiness or dizziness), as set out in Regulation (EC) No. 1272/2008.