Registration Dossier

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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:

Read across from strontium chloride to strontium hydroxide:

No studies for determination the sensitisation properties of Sr(OH)2have been performed and none are proposed, based on scientific considerations and for animal welfare reasons. In accordance with section 8.3, column 2, Annex VII of Regulation (EC) No. 1907/2006, the skin sensitisation study does not need to be conducted since the available information indicates that the criteria are met for classification as corrosive to the skin (pH≥11.5).

However, the sensitisation potential may reasonably be considered to be determined by availability of Sr2+cations.As a first surrogate for bioavailability, the water solubility of a test substance may be used. A sensitisation study is made available for strontium chloride hexahydrate. Strontium chloride hexahydrate is highly water soluble with ca. 1000 g/L at 0°C. Also the water solubility of strontium hydroxide is high (22.5 g/L at 25 °C for the anhydrous from and 20 g/L at 25 °C for the octahydrate form). Hence, any read across from strontium chloride to strontium hydroxide is considered to be justified and will likely lead to rather conservative no-effect levels.


The study conducted with strontium chloride causes no sensitising effects to skin. Due to the possibility of read-across it can be stated that strontium hydroxide as such has no sensitising potential.

Justification for selection of skin sensitisation endpoint:
Only one study available. Read-across from strontium chloride to strontium hydroxide is performed.

Justification for classification or non-classification


The reference Allen (1997) is considered as the key study on skin sensitisation and will be used for classification. The overall sensitisation results are as follows:

The test material, Strontium chloride-6-hydrate extra pure, produced a 0 % (0/10) sensitisation rate and was classified as a non-sensitiser to guinea pig skin. According to the criteria specified by Directive 67/548/EEC and subsequent regulations, the test item is not classified as skin sensitizer. According to the EC Regulation No. 1272/2008 and subsequent regulations, the test item is not classified as Category 1. Based on read-across from strontium chloride to strontium hydroxide, strontium hydroxide is also not classified as skin sensitizer.


Respiratory sensitisation:

During long-year industrial practice no cases of hypersensitivity were observed till now by workers exposed exclusively to strontium hydroxide. Thus, no classification as respiratory sensitiser according to regulation (EC) 1272/2008 is required.