3-methylbut-2-en-1-ol

Endpoint summary

Description of key information

Skin irritation: 
In vitro (EpiDerm), 3 and 60 minutes: corrosive (OECD 431 / Draft 1999, BASF61H0274/002326) 
Eye irritation:
In vivo, rabbit (no washing out): risk of serious damage to eyes (similar to OECD 405, BASF78/453).  

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Additional information

There are valid data available for the assessment of the skin and eye irritation potential of 3-methylbut-2-en-1-ol.

Skin irritation:

In the key study, an in vitro EpiDerm Skin Corrosivity Test according to OECD 431 / Draft 1999, 3 -methylbut-2 -en-1 -ol was assessed by a single topical application of 25 µL bulk volume (about 10 mg) to a reconstructed three dimensional human epidermis model for 3 minutes and 1 hour (BASF61H0274/002326). Based on the study results, it was concluded, that 3 -methylbut-2 -en-1 -ol does show a corrosive potential in the EpiDerm skin corrosivity test under the test conditions chosen.

 

As supportive study, an in vivo skin irritation study similar to the protocol of OECD 404 (2002) with the deviations of different application time (1, 5, 15 min and 20 hrs instead of 4 hrs), animal number (2 instead of 3), observation period (8 instead of 14 days), and treatment conditions (occlusive instead of semiocclusive conditions) is available (BASFXX/24). Undiluted 3 -methylbut-2 -en-1 -ol was applied to the shaved skin of 2 Vienna White rabbits in a occlusive dressing for the exposure period of 1, 5, 15 min and 20 hrs. The animals were observed following exposure for 8 days. Skin changes were recorded after removal of the patch after 1h, 24, 48, and 72 hrs, as well as after 6 and 8 days.

After 15 minutes occlusive treatment a reversible erythema (score = 2.67 and 3) as well as a reversible edema (overall score = 2) was determined during the relevant reading period (24 - 72 hours) in animal 1 and 2, respectively. Strong scaling and crust were observed at the end of the observation period ( 8 days).

After the 20 hours occlusive treatment, necroses were detectable in both animals 24 hours after test substance removal and at the end of the observation period (8 days), indicating the corrosive potential of 3 -methylbut-2 -en-1 -ol under stringent testing conditions (20 hour occlusive application).

 

A further supportive skin irritation study was performed similar to the protocol of OECD 404 with the deviations of a different observation period (8 instead of 14 days), and treatment conditions (occlusive instead of semiocclusive conditions) (BASF78/453). Undiluted test substance was applied to the shaved skin of 4 Vienna White rabbits under occlusion for the exposure period of 1 and 4 hours. The animals were observed following exposure for 8 days. Skin changes were recorded after removal of the bandage as well as after 24 hrs, 48 hrs, 5d, 6d and 8d.

The presence of parchment-like necroses as well as severe erythema (score = 4 in 2/4 and 3/4 animals) at the end of the observation period of 8 days, after a one and 4 h application indicates a strong skin irritating potential of the test compound, 3-Methylbut-2-en-1-ol.

Two further studies in rabbits, reported as short summaries from secondary sources provide additional evidence for a strong irritating potential of 3 -methylbut-2 -en-1 -ol (RhonePoulencBC0978; Moreno 1977)

Based on the in vitro findings from the EpiDerm skin corrosivity test and the supportive evidence from in vivo skin irritation studies, 3 -methylbut-2 -en-1 -ol was assessed to be corrosive to the skin.

 

Eye irritation:

In the key study, an eye irritation study performed similar to the OECD Guideline 405 (BASF78/453), 0.1 mL of the undiluted substance was applied to the eyes of 3 Vienna White rabbits. The test substance was not washed out and induced cornea opacity (mean scores of 1.0), moderate conjunctival redness (mean scores of 1.67 to 2.0), no iritis (score 0.0) and moderate chemosis (mean score 1.33) during the relevant reading period (24 -72 h). The changes were not completely reversible within a post observation period of 8 days. One animal showed corneal opacity (score 2), two animals showed slight conjunctiva redness (score 1) and one animal showed grade 1 chemosis. As these effects observed were not fully reversible within the given observation period, 3-methylbut-2-en-1-ol has the potential for a risk of serious damage to the eyes.

In a supportive, non-guideline study eye irritation study (BASFXX/24), the undiluted test substance was applied to the eyes of two Vienna White rabbits at a volume of 0.05 mL and the eye was not washed out. This treatment led to corneal opacity and moderate redness and edema in the rabbit eye 24 hours after treatment. The findings were reversible after 8 days except slight conjunctiva redness which is expected to be reversible within 21 days. Under the test conditions chosen, 3-methylbut-2-en-1-ol showed an irritating potential to the eyes of rabbits.

Respiratory irritation:

There are no data available concerning the irritating potential to the respiratory system.

 

Conclusion

The undiluted 3-Methylbut-2-en-1-ol was corrosive to the skin. In the eye, the undiluted test substance was highly irritating and has a risk of serious damage to the eyes.

Effects on skin irritation/corrosion: corrosive

Effect level: empty Endpoint conclusion: Adverse effect observed

Justification for classification or non-classification

Based on the results of the available skin irritation studies, 3 -Methylbut-2 -en-1 -ol has to be classified as corrosive according to requirements of the EU Annex VI of directive 67/548/EEC (R34, "Causes burns") and 1272/2008/EEC criteria (Cat. 1C), respectively.

According to 67/548/EEC and 1272/2008/EEC, when a substance is classified as corrosive and assigned R34 and Cat 1C, the risk of severe damage to eyes (R41; “Risk of serious damage to eyes” and Cat. 1; “serious eye damage/eye irritation”) is considered implicit.