Registration Dossier

Diss Factsheets

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

As N2O is a gas, sensitisationviaskin is not considered relevant. Furthermore, the wealth of available human data on N2O does not indicate that the substance is a skin sensitiser.


Justification for selection of skin sensitisation endpoint:
Study scientifically unjustified. N2O is a gas and as such the route of exposure is not relevant

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

Markers of respiratory sensitisation are manifest in the form of respiratory reactions including asthma, rhinitis and alveolitis. From the animal data available there is no evidence to suggest that N2O is a respiratory sensitiser. Such studies confirm that N2O effects the respiratory system via depression of the ventilatory response in the presence of hypoxia, rather than one of sensitisation.


Justification for selection of respiratory sensitisation endpoint:
Currently no validated in vivo methods available.

Justification for classification or non-classification

As N2O is a gas, skin sensitisation is unlikely to be a relevant endpoint. Whilst no in vivo respiratory sensitisation data exist, N2O reacts directly with methionine synthase (MS) and therefore is unlikely to have any direct effects on acute pulmonary function / lung tissue. The effects seen following exposure to N2O are attributed to the dilution of oxygen from inhaled air, causing hypoxia, rather than lung targeted toxicity. Therefore,N2O has not been classified as a skin or respiratory sensitiser and no classification is therefore required.