Butan-2-ol

Endpoint summary

Description of key information

A skin irritation study on s-butanol in rabbits, which was performed according to test guidelines, has demonstrated that the compound is not irritating to rabbit skin. 
s-Butanol induced serious eye damage in 1 out of 6 rabbits after a single application in a study performed according to test guidelines. Mild reversible irritation was observed in all other animals. Therefore, s-butanol is considered to be a reversible eye irritant.  

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin irritation:

A skin irritation study on s-butanol has been performed in accordance with OECD Guidelines for the Testing of Chemicals No. 404 and in compliance with GLP (Price, 1986).  In this study, 3 male and 3 female New Zealand White rabbits were exposed to 0.5 mL of undiluted s-butanol on the shorn dorsal region under semi-occlusive conditions.  Animals were exposed to the test compound for 4 hours and observations were recorded at 4, 24, 48, and 72 hours and 7 days after application. Skin reactions were scored according to a prescribed numerical system. In all animals, no skin reactions were observed following the application of s-butanol to rabbit skin for 4 hours. Based on the results of this study, the authors stated that s-butanol is a non-irritant to rabbit skin. s-Butanol is not classified as a skin irritant according to the CLP classification criteria.

 

 

Eye Irritation:

 

An eye irritation study on s-butanol has been performed in accordance with OECD Guidelines for the Testing of Chemicals No. 405 and in compliance with GLP (Price, 1986).  In this study, 0.1 mL of undiluted s-butanol was instilled into one conjunctival sac of each of 3 male and 3 female New Zealand White rabbits.  Ocular changes were assessed 1, 4, 24, 48, and 72 hours and 7 days after treatment, and scoring was performed according to guideline methods. 

Instillation of s-butanol caused moderate initial pain and induced moderate conjunctival inflammation with some discharge in all animals within 1 hour of dosing. The swelling and discharge had largely cleared by 4 hours; however, redness persisted in 3 animals up to 7 days after treatment. These animals and one other animal had impaired iritic response and/or slight corneal opacity between 24 and 72 hours after treatment. These effects were cleared by 7 days in all except for one animal, which had an intensely opaque eye over the entire cornea with no iritic response. Recovery was considered not possible, and thus, this animal was killed for humane reasons. All ocular effects observed in the remaining rabbits were fully reversible by 14 days. The mean scores at 24, 48, and 72 hours are 1.5, 0.3, 0.5, and 0.2 for redness, chemosis, corneal opacity, and iritic effects, respectively. Under the conditions of this study and in view of the response in one animal, s-butanol was considered by the investigators to be corrosive to rabbit eyes. However, considering that only mild, reversible irritation (insufficient to classify) was observed in the majority of animals (5 out of 6), the irreversible effects observed in one animal were likely resultant of an idiosyncratic reaction. It is unclear from this study whether the lack of reversibility is directly related to the test compound. Therefore, s-butanol is considered to be a reversible eye irritant. s-Butanol is classified as a Category I (causes serious eye damage) according to the CLP classification criteria.

Respiratory Irritation:

Sensory and pulmonary irritation potential of s-butanol at concentrations up to 15300 ppm were investigated in groups of trachea-cannulated or non-cannulated mice (Hansen and Nielsen, 1993). Based on this publication, a weak potential for respiratory irritation was reported; however, further data to justify a classification for respiratory tract irritation was not available. 

Effects on eye irritation: irritating

Justification for classification or non-classification

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

Eye irritation: According to CLP classification criteria, this substance does meet the criteria for classification and labelling for this endpoint (category II: causes serious eye irritation), as set out in Regulation (EC) No. 1272/2008.

Respiratory irritation: According to CLP classification criteria, the substance does meet the criteria for classification and labelling for this endpoint (STOT single exposure category 3, H335 - May cause respiratory irritation), as set out in Regulation (EC) No. 1272/2008.