Reaction mass of divinylbenzene and ethylstyrene

Endpoint summary

Description of key information

A GLP-study according to OECD guideline 401 is available for DVB-96. In addition two non-GLP studies equivalent to OECD guideline 401 are available for DVB-HP and DVB-55. Two non-GLP studies equivalent or similar to OECD guideline 403  and one non-GLP study equivalent to OECD guideline 402 are available for DVB-55.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

17 600 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

8 000 mg/kg bw

Additional information

The oral LD50 values for different grades of the reaction mass of divinylbenzene and ethylstyrene in rats ranges from >2000 to 4100 mg/kg. The grades tested cover the highest concentration of divinylbenzene (DVB-96: 96% divinylbenzene and 4% ethylstyrene) and ethylstyrene (DVB-55: 55% divinylbenzene and 45% ethylstyrene). All oral LD50s were greater than 2000 mg/kg.

Both acute inhalation studies available for DVB-55 were conducted equivalent or similar to OECD guideline 403 with some deviations regarding the exposure duration and temperature of the vapor. In one study the highest dose tested was 5 mg/l which did not lead to any mortality in rats. However, in mice an LC50 between 0.8 and 2.3 mg/l can be estimated from that study.

In a second study DVB-55 concentrations up to 17.6 mg/l administered over 7 hours at 80°C did not cause any mortality in male rats, whereas 25.7 mg/l administered over 7 hours at 100°C killed 3 of 5 male rats. One of 5 female rats died after 2 hours exposure to 144 mg/l DVB-55 at 130°C. Based on the available data and considering the exposure conditions (duration and temperature), there is no clear evidence that the LC50 would be smaller than 20 mg/l under normal conditions. The LC50 in rats is greater than 17.6 mg/l.

A dermal LD50 of 8000 mg/kg bw was established for DVB-55 in a non-GLP study equivalent to OECD guideline 402. This is the only grade of this reaction mass which was tested for acute toxicity via the dermal route. However, DVB-55 contains both components of the reaction mass at equivalent concentrations. Based on the high LD50 for the reaction mass of 55% divinylbenzene and 45% ethylstyrene, it can be concluded that the other grades of the reaction mass (DVB-63 and DVB-HP), containing up to 80% divinylbenzene, are not acutely harmful via the dermal route.

Justification for classification or non-classification

LD50 values for oral and dermal route are greater than 2000 mg/kg/bw and the LC50 value is greater than 17.6 mg/l with no clear evidence for an LC50 value < 20 mg/l. According to the EU criteria for classification and labeling, the reaction mass of divinylbenzene and ethylstyrene is not classified for acute toxicity for any route of exposure.