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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Description of key information

Based on the same behaviour and toxicological effects, a read across with ZrO2 is performed. No effect was observed following repeated inhalation of ZrO2.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

The justification for the use of Zr/ ZrO2 data as a read across approach was developped in the toxicological summary.

In addition, particle size influences the deposition behaviour in the respiratory tract and potential toxic effects.

The Hf powder particle size was found to be generally between 44 µm and 0.8 mm.(see section 4.5 of the dossier)

In the Spiegl et al. study (1956), the D50 or mass median aerodynamic diameter was set to 1.5 µm for ZrO2. Thus, ZrO2 particles will be able to reach lower parts of the respiratory system. The use of data from ZrO2 particles ("alveolar particles") is toxicologically protective or toxicologically equivalent (for some Zr powder during the manufacturing process) for Hf powder.

One reliable study (Spiegl et al., 1956 - Klimlisch 2) described a 30 day and 60 day repeated dose inhalation test in several animal species. Exposition to 75 mg Zr/m3 (100.8 mg/m3 ZrO2) for 30 days or 11 mg Zr/m3 (15.4 mg/m3 ZrO2) for 60 days produced no significant effect on animal mortality, rate, growth, haematology values or histopathology. The NOAEC were deemed to be greater than the concentration tested.

Another study scored Klimlisch (Delongeas et al., 1983) confirmed the absence of effects on mortality, behaviour and growth, following daily instillation of 800 mg/kg zirconium oxychloride (230 mg Zr/ kg/day) via gastric tube, for 16 days.

As 30 day and 60 day studies are available, no longer studies were necessary, taking into account the low toxicity of this substance.

Justification for classification or non-classification

Substances should be classified in category 2 for specific target organ toxicity (repeated exposure) on the basis of observations from appropriate studies in experimental animals in which significant toxic effects, of relevance to human health, were produced at generally moderate exposure concentrations. Based on the available data and the absence of toxicity effects observed, the substance was not classified under the CLP Regulation 1272/2008 and the directive Classification and Labelling 67/548/EC.