Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Description of key information

skin irritation: substance was applied into the inside of the ear of a rabbit; result: highly corrosive
eye irritation: the undiluted substance was placed into the conjunctival sac of a rabbit; result: highly corrosive

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (irritating)

Additional information

n-Butyl isocyanate is corrosive to skin and eyes of rabbits. The toxicity studies and one case report indicate that n-butyl isocyanate vapor causes irritation of the respiratory tract. RD50 values for rat and mice of 40.4 mg/m³ and 38.9 mg/m³, respectively, were determined and gave evidence for a moderate sensory irritation potential of n-butyl isocyanate. 1 mg/m³ (RD50 x 0.03) was regarded as the threshold for sensory irritation in humans.


Effects on skin irritation/corrosion: highly corrosive

Effects on eye irritation: highly corrosive

Justification for classification or non-classification

due to the results of the key study for skin irritation/corrosion R34 is justified

due to the severe effects on the eye R41 is adequate; however as the substance is labelled with R34 and additional labelling with R41 is not necessary.

Therefore for skin and eye irritation/corrosion a labelling with R34 is sufficient