Methyloxirane

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

A small number of cases in workers provide some limited evidence that repeated dermal exposure to liquid propylene oxide may cause skin sensitisation(Jensen, 1981; van Ketel, 1986; Steinkraus and Hawsen, 1994), however a study conducted in animals did not find skin sensitisation effects (Dow Chemical Company, 1982).

The skin sensitisation study was performed in guinea pigs according to a modification of the Maguire method (Dow Chemical Company, 1982). The study examined one positive control group and one test group. The test group received 4 applications of a 10% solution of propylene oxide applied on a gauze square and covered by tape. The positive control group received DER 331 epoxy resin as a 10% solution in the same way as the test group. After 2 days, a second application was administered. At the time of the third application 0.2 ml of Freund's Adjuvant was injected intradermally adjacent to the insult site. Every time the patches were removed, observations about primary irritation were made and recorded. After two weeks of rest the animals were challenged and the skin response was scored 24 and 48 hours after the challenge. A positive response indicative of sensitisation (slight/moderate redness) was observed on 8 of l0 guinea pigs treated with DER 331. None of the 10 guinea pigs treated with the propylene oxide solution revealed signs of sensitisation. Therefore as a 10% solution this material is not considered a potential human skin sensitiser.

Migrated from Short description of key information:
Based on the result of the modified Maguire method test with guinea pigs, propylene oixde is not sensitising to skin.

Respiratory sensitisation

Endpoint conclusion

Additional information:

No data on respiratory sensitisation are available. However, in accordance with Section 1 of REACH Annex XI, the study is scientifically unjustified, as respiratory tract sensitisation is not expected based on the fact that propylene oxide is not skin sensitiser and no human data are available indicating a concern for respiratory sensitisation.

Justification for classification or non-classification

Based on the absence of skin sensitising effect in a modified Maguire method study with guinea pigs and the lack of data indicating the respiratory sensitisation of propylene oxide, classification according to EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 is not warranted.