Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Key and read-across skin sensitisation studies are available for 2 -methylbutaneandn-pentane. For 2 -methylbutane, young adult Hartley albino guinea pigs (20 females per dose) were tested using the Guinea Pig Maximization Test method (Trimmer et al., 1991). Guinea pigs were exposed to the test material via induction twice to allow for development of sensitisation, then challenged and compared to the control group and examined for signs of dermal irritation. There was no evidence of dermal irritation or sensitisation in this study. 2-Methylbutane is not a dermal sensitizer.

For n-pentane, a study was conducted using guinea pigs (20 females/dose; 15 females for positive control; Trimmer, 1991). For the induction phase, six intradermal injections (0.1 mL each) were administered to three different sites as follows: Site 1: FCA/water to treated and control groups; Site 2: 5.0% n-pentane in carrier (ethanol) to the treated group, 100% ethanol to the control group; Site 3: 5.0% n-pentane in FCA/Water to the treated group, 5.0% carrier (reverse osmosis water) in FCA/Water to the control group. On day 7 following injection, 0.5 mL of a mild to moderately irritating dose of n-pentane was administered topically over the previously injected areas and covered with occlusive wrapping. Control animals received topical carrier applications instead. The challenge phase was conducted 21 days post induction phase. n-Pentane (0.1 mL of n-pentane; 1.0% in ethanol) was applied topically to the left flank of both treated and control irritation groups. All animals survived to study termination and displayed a weight gain from their day 0 values. Abnormal clinical observations during scheduled intervals were limited to one treated group animal that was emaciated and had a small amount of stool. Another animal exhibited slight emaciation and poor food consumption. Clinical signs observed in these two animals were considered to be correlated to the stress of the wrapping procedure and not treatment-related. No signs of dermal irritation were observed at any dose in either patch group. DNCB elicited positive reactions from all tested animals 24 and 48 hours after removal of the patch challenge. Based on the lack of signs dermal irritation observed in the study, n-pentane was not considered a dermal sensitiser.


Migrated from Short description of key information:
Key skin sensitisation studies are available for 2-methylbutane (OECD 406 and EU Method B.6); read-across skin sensitisation studies also were identified fro n-pentane (OECD 406). All studies showed that test substances were found not to be dermal sensitizers in guinea pigs.

Respiratory sensitisation

Endpoint conclusion
Additional information:

Respiratory sensitisation is not a standard information requirement.


Migrated from Short description of key information:
No data identified.

Justification for classification or non-classification

Based on negative results from a key skin sensitisation study, 2-methylbutane is not considered to be a skin sensitizer and do not meet the criteria for classification as a dermal sensitizer under EU Dangerous Substances Directive 67/548/EEC or CLP EU Regulation 1272/2008. There are no data available for respiratory sensitisation for 2-methylbutane.