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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Toxicological information


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Administrative data

Description of key information

Members of the C4 high 1,3-butadiene category show low sub-chronic toxicity and low potential for neurotoxicity. Inhalation exposure is the most relevant route. No significant exposure-related toxicological or neurotoxicological effects have been observed in inhalation studies of up to 90 days duration on the constituent substances butane and isobutane. 

Key value for chemical safety assessment

Additional information

Repeat dose toxicity data with neurotoxicity assessments are available for two of the constituent substances of the C4 high 1,3-butadiene category (butane and isobutane).   No systemic toxicity (i.e., no affect on survival, haematological or clinical chemistry parameters, food consumption, body weight, organ weight, and histopathology) or neurological effects (as measured by clinical observations, functional observational battery, and motor activity) were observed in 6-week studies to modern guidelines and GLP in which isobutane, butane and were administered to rats by inhalation. The NOAECs for both studies were the maximum dose levels tested (9000 ppm, 21,394 mg/m3) (HLS 2008, 2010).

Justification for classification or non-classification

Members of the C4 high 1,3-butadiene category are flammable gases at room temperature and therefore dermal and oral exposure is unlikely. They have low sub-chronic inhalation toxicity and studies which included evaluation of neurotoxicity parameters indicate low potential for neurotoxicity. Classification under CLP is not warranted.