Reaction mass of 1,1'-oxybis(ethylbenzene) and Styrene, oligomers

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

SMPO Heavy ends was tested in the Mouse Local Lymph Node Assay according to OECD No.429 (Latour, 2015c). Test substance concentrations selected for the main study were based on the results of a pre-screen test. In the main study, three experimental groups of five female CBA/J mice were treated with test substance concentrations of 25, 50 or 100% w/w on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with vehicle alone (Acetone/Olive oil (4:1 v/v)). Three days after the last exposure, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised and pooled for each animal. After precipitating the DNA of the lymph node cells, radioactivity measurements were performed. The activity was expressed as the number of Disintegrations Per Minute (DPM) and a stimulation index (SI) was subsequently calculated for each group. No irritation of the ears was observed in any of the animals examined.

All auricular lymph nodes of the animals of the control group were considered normal in size. The nodes of all experimental animals were considered enlarged. The largest auricular lymph nodes were found in the higher dose groups. No macroscopic abnormalities of the surrounding area were noted for any of the animals.

Mean DPM/animal values for the experimental groups treated with test substance concentrations 25, 50 and 100% were 4753, 5300 and 11214 DPM, respectively. The mean DPM/animal value for the vehicle control group was 520 DPM. The SI values calculated for the substance concentrations 25, 50 and 100% were 9.1, 10.2 and 21.6, respectively. These results indicate that the test substance could elicit a SI = 3. The data showed a dose-response and the EC3 value (the estimated test substance concentration that will give a SI =3) was established to be between >0 and 25%.

Migrated from Short description of key information:
SMPO Heavy ends was tested in the Mouse Local Lymph Node Assay according to OECD No.429. Three experimental groups of five female CBA/J mice were treated with test substance concentrations of 25, 50 or 100% w/w on three consecutive days, by open application on the ears. All auricular lymph nodes of the animals of the control group were considered normal in size. The nodes of all experimental animals were considered enlarged. The largest auricular lymph nodes were found in the higher dose groups. No macroscopic abnormalities of the surrounding area were noted for any of the animals.
Mean DPM/animal values for the experimental groups treated with test substance concentrations 25, 50 and 100% were 4753, 5300 and 11214 DPM, respectively. The mean DPM/animal value for the vehicle control group was 520 DPM. The SI values calculated for the substance concentrations 25, 50 and 100% were 9.1, 10.2 and 21.6, respectively. These results indicate that the test substance could elicit a SI = 3. The data showed a dose-response and the EC3 value (the estimated test substance concentration that will give a SI =3) was established to be between >0 and 25%.

Justification for selection of skin sensitisation endpoint:
key study

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on these results and according to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments), SMPO Heavy ends should be classified as skin sensitizer (Category 1) and labelled as H317: May cause an allergic skin reaction. A further specification into 1A and 1B is not possible since the study data do not allow statement of severity of the effects.