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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Justification for grouping of substances and read-across

There are no data available on the skin sensitisation potential isononyl isononanoate. In order to fulfil the standard information requirements set out in Annex VII, 8.3, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across from structurally related substances was conducted.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular for human toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 whereby substances may be predicted as similar provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity.

Overview of skin sensitisation


Chemical name

Molecular weight


(previously 42131-25-9) (a)

Isononyl isononanoate

ca. 285


RA: CAS 59219-71-5
RA: CAS 91031-48-0

91031-48-0 (b)

Fatty acids, C16-18, 2-ethylhexyl esters

368.65; 396.70

Experimental result:
not sensitising


3,5,5-trimethylhexyl 3,5,5 -trimethylhexanoate


Experimental result:
not sensitising

(a) The substance subject to registration is indicated in bold font.

(b) Reference (read-across) substances are indicated in normal font. Lack of data for a given endpoint is indicated by “--“.

The above mentioned substances are considered to be similar on the basis of the structural similar properties and/or activities. The available endpoint information is used to predict the same endpoints for isononyl isononanoate.

A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).



Skin sensitisation

CAS 91031-48-0

Fatty acids, C16-18, 2-ethylhexyl esters (CAS 91031-48-0) was tested for its skin sensitisation potential in a Guinea pig maximization test according to OECD Guideline 406 (Clouzeau, 1991). 20 test and 10 control animals (Dunkin-Hartley guinea pigs) were induced intradermally with the test substance in a 25% dilution in paraffin oil. 7 days later the epidermal induction was performed with the undiluted test substance, as this concentration (100%) was found to be slightly irritating in the range finding test. 12 days after the last induction treatment the animals were challenged with a 50% test substance solution in paraffin oil. 24 and 48 hours after the challenge exposure ended, no indications of a skin sensitising potential of the test substance was observed in any animal.

CAS 59219-71-5

The sensitising potential of 3,5,5-trimethylhexyl 3,5,5-trimethylhexanoate (CAS 59219-71-5) was assessed in a Repeated Insult Patch Test (epicutaneous test) performed in 98 human volunteers (29 males, 89 females) (Harrison, 1997). During the induction phase, volunteers were exposed in total nine times at an average of 3 times/week. An occlusive patch with 0.2 mL of the undiluted test substance was applied to the left scapular area for 24 hour. The challenge was performed approximately two weeks after the last induction. The challenge patch was applied to the right scapular area and remained in place for 24 h. The sensitisation reaction at the challenge site was assessed 0, 24, 48 and 72 h after patch removal. During the induction phase, 4/98 exhibited faint, minimal erythema or erythema (score ± or 1) and 2/98 had hyperpigmentation. Following the challenge treatment, 11/98 exhibited faint, minimal erythema or erythema (score ± or 1). These reactions are considered to be irritation reactions. The test material did not induce skin sensitisation in any of the 98 subjects.  

Conclusions for skin sensitisation

No studies assessing the skin sensitising properties of isononyl isononanoate are available. A Guinea Pig Maximisation Test was performed with the analogue substance Fatty acids, C16-18, 2-ethylhexyl esters (CAS 91031-48-0), in which no skin sensitisation was induced (Clouzeau, 1991). The results of a Repeated Insult Patch Test (epicutaneous test) performed in 98 human volunteers with the analogue substance 3,5,5-trimethylhexyl 3,5,5-trimethylhexanoate (CAS 59219-71-5) show the substance had no skin sensitising effects (Harrison, 1997). Taking all the available data into consideration, isononyl isononanoate is considered not to be a skin sensitiser.

Migrated from Short description of key information:
Skin sensitisation (OECD 406): not sensitising (based on read-across from CAS 91031-48-0 and from CAS 59219-71-5, human data)

Justification for selection of skin sensitisation endpoint:
Hazard assessment is conducted by means of read-across from structural analogues and based on the weight of evidence from all available studies.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:
Justification for selection of respiratory sensitisation endpoint:
Study not required according to Annex VII-X of Regulation (EC) No 1907/2006.

Justification for classification or non-classification

Based on read-across from the structurally similar substances, the available data on skin sensitisation do not meet the classification criteria according to Regulation (EC) 1272/2008 or Directive 67/548/EEC, and are therefore conclusive but not sufficient for classification.

There are no data available on respiratory sensitisation.