Registration Dossier

Administrative data

Description of key information

Members of the C4 high 1,3-butadiene category are flammable gases at room temperature and therefore the requirement for data on skin and eye irritation is waived in accordance with REACH Annex XI. Data are available on one of the streams in this category (all CAS numbers are; 68476-52-8, 68477-42-9, 68955-28-2, 87741-01-3, 92045-23-3) and indicate that the irritation potential of this category is low. All members of this category are gases, and liquid gases may cause burns and frostbite due to the extreme cold of the liquid.

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:
no adverse effect observed (not irritating)

Additional information

In accordance with Section 2 of REACH Annex XI, studies on skin and eye irritation do not need to be conducted as members of the C4 high 1,3-butadiene category (CAS numbers; 68476-52-8, 68477-42-9, 68955-28-2, 87741-01-3, 92045-23-3) are flammable gases at room temperature. 

However, skin and eye irritation studies have been conducted on one of the streams in this category. Butadiene Concentrate (CAS no. 68955-28-2) was not irritating to rabbit skin or eyes (Mobil 1985). The available data on one of the component substances,1,3-butadiene, also indicates that it is not irritating (EU RAR, 2002).Humans exposed to1,3-butadieneat 2000 ppm (4425 mg/m3) and 4000 ppm (8851 mg/m3) described slight smarting of the eyes and difficulty in focusing although at 8000 ppm (17,702 mg/m3) no subjective symptoms were reported (Carpenter et al, 1944).Rapid evaporation following application of these substances is likely so the value of these studies is questionable. No data are available on the other component substances (butene isomers and butane), but based on physical chemical properties, the liquid gases may cause burns and frostbite due to the extreme cold of the liquid. There are no indications of irritation from repeat dose inhalation studies.


Effect level: empty Endpoint conclusion: Adverse effect observed

Justification for classification or non-classification

Members of the C4 high 1,3-butadiene category are flammable gases at room temperature. There are sufficient data available to conclude that streams within the C4 high 1,3-butadiene category are not irritating therefore do not warrant classification under Dir 1999/45/EC or GHS/CLP.