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Administrative data

Description of key information

Reliable, adequate and relevant studies from various analogue substances, demonstrate a lack of irritation/corrosion potential of the substance zind didocosanoate.

Key value for chemical safety assessment

Skin irritation / corrosion

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

Eye irritation

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

Respiratory irritation

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

Additional information

ZINC DIDOCOSANOATE:

Zinc didocosanoate (synonym: zinc behenate, CAS 16529-65-0) is a zinc salt of a fatty acid containing approximately 22 C-atoms. Thus, read-across of data available for zinc salts of similar fatty acid chainlength (i.e. Fatty acids, C16 -18, zinc salts) based on structural similarity, water solubility and zinc content in a conservative, worst-case approach is assumed to adequately describe the skin and eye irritation potential of zinc didocosanoate.

The irritation and corrosion potential is described with information read-across from relevant zinc soaps (zinc salts of similar chainlength) as well as supporting information from slightly soluble/insoluble zinc compounds. A 1:1 read-across of toxicological data of (i) Fatty acids, C16 -18, zinc salts; and (ii) zinc oxide is applied to zinc didocosanoate as it is assumed that zinc didocosanoate liberates ionic zinc and its fatty acid tetradecanoate moiety upon contact with (mucous) biological membranes. Consequently, following the worst-case approach, the studies on the fatty acid zinc salt with highest zinc amount and lowest pH of the non-saponified free fatty acid were selected. In addition, the results of the histopathological examination of lung tissue following acute exposure to zinc dilaurate (C12) via inhalation (OECD 436 test) do not indicate an irritative potential. Furthermore, zinc didocosanoate is not expected to be irritating to the skin or the eye based on the lack of respective irritation potential of slightly soluble/insoluble zinc compounds. Thus, a lack of skin, eye and respiratory irritancy is considered for zinc

didocosanoate and classification according to Regulation (EC) 1272/2008 is not required.

These conclusions are in line with conclusions for the structural analogue (i.e. Fatty acids, C16-18, zinc salts) from EU Risk assessment report “Zinc stearate (CAS# 91051-01-3, CAS# 557-05-1) Part II – Human Health.EUR 21168 EN (http://echa.europa.eu/documents/10162/08799aec-42c5-44e0-9969-baa022c66db1):

"It is consequently concluded that zinc distearate is not likely to have eye and skin irritation potential and, therefore does not need to be classified/labelled... Zinc distearate is not corrosive to skin or eyes."

A similar lack of skin and eye irritancy is considered for zinc didocosanoate. For a comprehensive overview of the (non) irritancy of zinc, see the hazard assessment of "Zinc" within the framework of Regulation (EC) No 1907/2006 cited below.

 

 

ZINC:

Based on the available information it appears that the slightly soluble zinc oxide and insoluble zinc sulphide are not skin irritants and therefore slightly soluble zinc hydroxide, zinc phosphate, zinc carbonate and zinc metal are also expected to be not irritating to skin. Zinc oxide, zinc phosphate, zinc metal and zinc sulphide are not eye irritants and therefore zinc carbonate and zinc hydroxide are also expected to be not irritating to eyes. None of the slightly soluble or insoluble zinc compounds appear to cause respiratory tract irritation.

 

The slightly soluble and insoluble zinc compounds (zinc oxide, zinc hydroxide, zinc phosphate, zinc carbonate, zinc metal and zinc sulphide) are not corrosive based on the available irritation data.

Justification for classification or non-classification

Zinc didocosanoate as slightly soluble/insoluble zinc compound is not irritating or corrosive based on the available irritation data. Therefore, classification is not required for irritation or corrosion according to EC criteria outlined in CLP Regulation (EC) No 1272/2008 and Directive 67/548/EEC.