Registration Dossier

Administrative data

Description of key information

Based on assessment of the available data for 2-methylbut-2-ene (2M2B) should be considered as mildly irritating to skin and non-irritating to eyes.  The respiratory tract irritation potential of 2M2B is not known, as no data are available for this endpoint. 

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (irritating)

Eye irritation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Additional information

Skin Irritation

Studies in Animals

An occlusive patch test based on the method of Draize (1975) was used to assess the primary skin irritation induced by 2M2B applied neat. The mean erythema and oedema scores for abraded and non-abraded skin were 0.8 and 0.6 i.e. <2 and <1 respectively. The primary irritation score calculated according to the method of Draize was 1.79.

On this basis 2M2B may be regarded as being mildly irritating to rabbit skin. The erythema and oedema scores at 7 days were higher than those at 72 hours but at 7 days all the skin patches were beginning to dry out and flake. It is possible the animals scratching these areas was a contributory factor, resulting in the slightly higher erythema scores (SRC, 1980).

Studies in Humans

No human information available

Eye Irritation

Studies in Animals

The method of Draize (1963) was used to assess the eye irritancy of 2M2B in New Zealand White rabbits. Instillation of 2M2B into the eye resulted in a moderate initial pain response (grade 4) in all animals. Mean total scores for the responses of the conjunctiva, cornea and iris were 0.5, 0 and 0 (i.e. all ≤0.5) and based on these results, 2M2B should be considered as non-irritating to rabbit eyes (SRC, 1980).

Studies in Humans

No human information available

Respiratory Tract Irritation

No studies on respiratory tract irritation have been conducted with 2M2B.  From the acute inhalation study and repeat dose study (HLS, 2003) there is no specific evidence of acute irritation effects warranting classification.

 


Effects on skin irritation/corrosion: slightly irritating

Justification for classification or non-classification

Based on assessment of the available data, 2M2B does not warrant classification as a respiratory tract or eye irritant under DSD or CLP. 

For skin irritation, all responses were below the threshold scores for classification however on the basis of criteria that inflammation of the skin is also significant if it persists in at least two animals (implied of 3, i.e. 4 of 6) at the end of the observation time, classification Xi, R38 Irritating to skin is warranted under DSD and category 2 H315 causes skin Irritation under CLP.

There is no evidence of irritation to the respiratory tract and no classification is warranted.