Registration Dossier

Administrative data

Description of key information

Skin irritation / corrosion: not irritating, though substance is currently classified

Eye irritation: not irritating

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

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 hydroxide was slightly irritating to the skin. According to OECD Test #404 guidelines, compounds should be considered an irritants 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 was also conducted in rabbits according to OECD Test #405 guidelines (EPSL, 2008b). In this study, nickel hydroxide 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 hydroxide 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 (di)hydroxide. The studies were specifically designed to evaluate the health hazard likely to arise from exposure by dermal or ocular application. Results demonstrated that nickel (di)hydroxide 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.

The following information is taken into account for any hazard / risk assessment:

Although Ni dihydroxide is currently classified as a dermal irritant, the results of a recently completed GLP, OECD guideline-compliant study do not meet the criteria for classification according to the CLP regulation. A recently completed eye irritation study confirms this substance should not be classsified as an eye irritant.

Value used for CSA:

Skin irritation / corrosion: not irritating, though substance is currently classified

Eye irritation: not irritating

Justification for classification or non-classification

Although current classification isSkin Irrit. 2: H315 in the 1st ATP to the CLP, arecently completed in vivo dermal irritation study concluded Ni dihydroxide was not an irritant, suggesting it should not be classified for this endpoint. However, the existing harmonized classification is carried forward in this registration file.

A new in vivo eye irritation study confirms Ni dihydroxide should not be classified for this endpoint.