Phenol, 2,4-bis[(dodecylthio)methyl]-6-methyl-

Endpoint summary

Description of key information

Since there is no data on skin irritation/corrosion for the substance (EC 438-600-3) available, a read-across to the structural analogon 4,6-bis(octylthiomethyl)-o-cresol has been conducted. In a skin irritation study conducted according to the OECD Guideline 404 (Acute Dermal Irritation / Corrosion), It caused a slight irritation (mean 24-48-72 hour erythema score 1 in 2/3 animals), completely reversible within 7 days after treatment (Ciba Geigy Ltd, 861245).
In an eye irritation study conducted according to the OECD Guideline 405 (Acute Eye Irritation / Corrosion), it also caused a very slight irritation reaction (mean 24-48-72 hour conjunctivae score 1 in all 3 animals), completely reversible within 72 hours (Ciba Geigy Ltd, 861244).

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)

Additional information

No data on acute toxicity for the substance (EC 438-600-3) available. Read-across to 4,6-bis(octylthiomethyl)-o-cresol is applied.

The read-across substance differs in the length of the alkyl chain at the thio ether. Specifically, it is a C8 chain in comparison to a C12 chain in the target substance. Due to the shorter chain length, the molecule is smaller and predicted to be of slightly better solubility in water. Therefore, it is considered to be of better systemic availability which might result in a slightly higher toxicity compared to the target substance. As both C8 and C12 chains are metabolized via beta oxidation, both substances are predicted to have the same metabolites. Overall read-across is justified and it was accepted by the Competent Authority for ELINCS registration.

Skin irritation

In a Ciba Geigy Ltd. (1986) study of validity 1 performed according to the OECD Guideline 404 (Acute Dermal Irritation / Corrosion), 0.5 ml unchanged substance was applied to the shaved skin site of 3 male New Zealand White rabbits for 4 hours under a secured with semi-occlusive gauze patch (20 cm2). The untreated contra-lateral flank of the same animals, also covered with gauze patch, was used as control. The skin reaction was observed 1, 24, 48, and 72 hours and 7 days after removing the gauze patch, and evaluated according to the OECD scoring system. The only sign of irritation was a slight erythema reaction (mean 24-48-72 hour erythema score 1) observed in 2/3 animals, but fully reversible within 7 days. 

Eye irritation

In the Ciba Geigy Ltd. (1986) study of validity 1 performed according to the OECD Guideline 405 (Acute Eye Irritation / Corrosion), 0.1 ml unchanged Irganox 1520 was applied to the conjunctival sac of each one eye of 3 male New Zealand White rabbits (no wash out) while the remaining untreated one served as negative control. The ocular reactions were then evaluated 1, 24, 48, 72 hours and 7 days after instillation according to the OECD scoring system, and the body weight was recorded at start and on days 3 and 7 of the test. The animals were also checked daily for systemic symptoms and mortality. The only sign of ocular irritation was a slight conjunctival reaction (mean 24-48-72 hour conjunctiva score of 0.67) observed in all treated eyes, but was fully reversible within 72 hours after treatment.

 

Respiratory irritation

No data available

Justification for classification or non-classification

Based on the OECD scoring of the skin/eye irritation studies described aboved, there is no need for classification of the test substance for skin or eye irritation according to the EU Dangerous Substance Directive 67/548/EEC and to the CLP Regulation (EU) 1272/2008 as amended for the second time in Directive EC 286/2011.