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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Available data on tantalum pentoxide (target substance) indicate a lack of mutagenicity in all available in vitro assays (OECD 471, OECD 473). Additionally data on tantalum pentachloride point to a lack of mutagenicity in in vitro assays according to OECD 476 used in a read-across approach for the assessment of tantalum pentoxide.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

The data available for ditantalum pentaoxide (target substance) does not fulfil all requirements of REACH Annex VIII. Thus, data from tantalum pentachloride were used in a read-across approach. ditantalum pentaoxide was tested negative in a bacterial reverse mutation test (OECD 471; May 2001) and an in vitro chromosome aberration test (OECD 473; Hargitai 2013). Tantalum pentachloride was tested negative in an in vitro HPRT study (OECD 476),

Due to lower transformation/dissolution results for ditantalum pentaoxide than for tantalum pentachloride the resulting toxicity potential would also be expected to be lower. Therefore, the read across to the source substance Tantalum pentachloride is adequately protective. For more details refer to the read-across report attached to IUCLID section 13.

As negative data is available for the higher tier mammalian mutagenicity tests (OECD 473 and OECD 476 with Tantalum pentachloride), ditantalum pentoxide is considered to be non-mutagenic.

 Justification for selection of genetic toxicity endpoint

 GLP guideline study.

Supporting information

In a literature paper by Keçeli & Alanyali (2004), the cytotoxicity of several metal oxides was examined.

Kidney fibroblast cells from an African Green Monkey were used in the in vitro study. The cells were incubated, in the presence of Tantalum oxide coated glass platelets, for 7 days. The cells where then examined for differences in cell morphology and proliferation. The morphology did not change, although a lower rate of proliferation was seen compared to the control. It was not possible to determine if the test material is toxic to cells.


Justification for classification or non-classification

No genotoxic effects were observed in OECD guideline tests with Ditantalum pentoxide and Tantalum pentachloride. Based on the available data from the read-across partner and itself, Tantalum pentoxide does not warrant classification for mutagenicity.