Registration Dossier

Administrative data

Description of key information

- Oral and dermal toxicity: Data are waived in accordance with REACH Annex XI, because all compounds are gases at room temperature. Additionally, in accordance with REACH Annex VII a study with oral exposure is not required, if data about  acute inhalation toxicity are available. 
- Inhalation toxicity: All compounds are practically non-toxic; lowest LC50 for Butene (CAS 25167-67-3) and 2-Methylpropene (CAS 115-11-7): LC50 (rat, 4h) > 22.9 mg/L; LC50 of all other compounds above 285 mg/L.

Key value for chemical safety assessment

Additional information

ORAL AND DERMAL TOXICITY:

The main components of the Reaction Mass of Butane and Butene (Butene, CAS 25167-67-3; Butane, CAS 106-97-8; Isobutane, CAS 75-28-5; 2-Methylpropene, CAS 115-11-7) are gases at room temperature. Therefore, testing by the oral or dermal route is not possible and the requirement for data on acute oral and dermal toxicity is waived in accordance with REACH Annex XI. Additionally, in accordance with REACH Annex VII a study with oral exposure is not required, if data about acute inhalation toxicity are available.

 

INHALATION TOXICITY:

For all compounds experimental key studies about the acute inhalation toxicity were available. The lowest LC50 was described for Butene (CAS 25167-67-3) and 2-Methylpropene (CAS 115-11-7), as in the GLP guideline study with the isoform butene-2 the LC50 was > 23 mg/L for rats after 4 h of exposure [TNO, 1992]. No mortality and no abnormal clinical signs were observed during the 14 days observation period.

The LC50 value for rats after 4h exposure with Butane (CAS 106-97-8) was 568 mg/L and the LC50 value for mice after 2 h exposure with Isobutane (CAS 75-28-5) was 1237 mg/L. Additionally, for all compounds there are further studies, supporting, that the compounds are practically non-toxic after acute inhalation exposure. 

 

HUMAN DATA:

No quantitative acute oral or dermal data were identified. However, direct skin contact with liquefied material can cause burns and frostbite due to the extreme cold of the liquid.Little quantitative acute inhalation data were identified. These data suggest that at high concentrations, asphyxiation can occur as a consequence of oxygen deficiency,but the effects are fully reversible if exposure stops.

Justification for classification or non-classification

Since all compounds are gases at room temperature and pressure, as well as data about acute inhalation toxicity are available, oral and dermal toxicity are not considered. All compounds were of low acute toxicity by the inhalation route in both human and animal studies with LC50 values above the limit value. Therefore, a classification according to Annex VI of Directive 67/548/EWG or Annex I of Directive 1272/2008 (EU-GHS) is not required.