Nickel(III) oxy hydroxide

Endpoint summary

Description of key information

There are no in vivo studies available characterizing the irritating effects of Ni oxyhydroxide. 
The results of in vivo studies with Ni dihydroxide are read-across to Ni oxyhydroxide. Ni dihydroxide is currently harmonized classified as a dermal irritant. 

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

There are no in vivo studies available investigating the irritating effects of Ni oxyhydroxide. Ni oxyhydroxide is a mixed oxide between Ni oxide and Ni dihydroxide which are representing the boundaries for the read-across approach. Ni dihydroxide is currently classified for dermal irritation Ni oxyhydroxide is read-across to Ni dihydroxide.

Information characterizing the potential for nickel dihydroxide to cause irritation/corrosion generally indicates that the compound is only slightly or mildly irritating. This indication is based on the results of two guideline-based, GLP studies recently conducted by Eurofins Product Safety Laboratory (EPSL) evaluating eye and skin irritation potential. The skin irritation study was conducted in rabbits according to OECD Test #404 guidelines (EPSL, 2008a). Three healthy female rabbits were exposed via the skin to nickel dihydroxide to determine if the test substance had the potential to produce irritation. Erythema was noted in all test animals at the 30-60 minute time point, but not at the remaining time intervals (up to 72 hours). No edema was observed during the study (each animal scored as 0 at all time points). The overall incidence and severity decreased with time, and the effects were fully reversible within 24 hours. The resulting Primary Dermal Irritation Index (PDII) was 0.3, indicating that nickel dihydroxide was slightly irritating to the skin. According to OECD Test #404 guidelines, compounds such low values should be considered as irritants only if responses persist to the end of the observation period; however, findings of this study indicated effects were fully reversible significantly prior to the end of the observation period.

The eye irritation study with Ni dihydroxide was also conducted in rabbits according to OECD Test #405 guidelines (EPSL, 2008b). In this study, nickel dihydroxide was instilled into the right eye of three healthy female rabbits to determine the potential to produce irritation. No corneal opacity was observed in any of the animals, though all three animals tested exhibited iritis and positive conjunctivitis one hour after instillation. All observed effects were reversible; incidence and severity of irritation decreased with time and all animals were free of ocular irritation by Day 7. The results of the study indicated that nickel dihydroxide was mildly irritating to the eye under the conditions of the study., The OECD Test #405 guidelines state that extrapolation of these results to humans is only valid to a limited degree as in many cases the albino rabbit is more sensitive than humans to ocular irritants for corrosives.

Collectively, these two studies provide reliable, adequate information to assess the irritant/corrosive properties of nickel dihydroxide which can be read-across to Ni oxyhydroxide. The studies were specifically designed to evaluate the health hazard likely to arise from exposure by dermal or ocular application. Results demonstrated that nickel dihydroxide can cause minor irritation in laboratory settings. However, all observed effects were fully reversible and generally classified as “slight” or “minor,” thus indicating a limited potential for irritant/corrosive potential. This is in contrast to teh current harmonized classification of Ni dihydroxide as H315

Effects on skin irritation/corrosion: slightly irritating

Justification for classification or non-classification

There are no in vivo studies available which report about the possible eye and/or skin irritating effects of Ni oxyhydroxide. Due to the structural similarity Ni oxyhydroxide is read-across from Ni dihydroxide as worst-case assumption.