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:

Reason for read across from BaCl2 to BaSO4:

Skin sensitization data are available for the structural analogue, barium chloride.The toxicity of barium sulfate and barium chloride may reasonably be considered to be determined by availability of Ba2+cations. As a first surrogate for bioavailability, the water solubility of a test substance may be used. Barium chloride is known to be well water soluble whereas barium sulfate has a low solubility in water. The conclusion is that Ba2+ ions are more bioaccesible if BaCl2 is administered. Hence, read-across to BaSO4 is based on worst case considerations and will likely lead to rather conservative no-effect levels. Based on the available information, barium sulfate is expected to be not sensitizing to skin.

Respiratory sensitisation

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

Justification for classification or non-classification

Sensitisation:

The reference Stitzinger (2010) is considered as the key study on skin sensitisation and will be used for classification. The overall sensitisation results are as follows:

Local lymph node assay (LLNA) in mice

SIs of less than 3.0 (1.2 – 1.5) were observed at all test concentrations of barium chloride dihydrate (5, 10, 25 %) and no dose response could be observed. Therefore, an EC3 value (the estimated concentration required to induce a threshold positive response, i.e., SI = 3) for the test substance under the conditions of the study was not calculable. Thus, the classification criteria acc. to regulation (EC) 1272/2008 as skin sensitizer are not met and barium sulfate should not be labelled as such.

Respiratory sensitisation:

Based on an industry survey, during long-year industrial practice no cases of hypersensitivity were observed till now by workers exposed exclusively to barium sulphate. Thus, no classification as respiratory sensitiser according to regulation (EC) 1272/2008 is required.