Divinylbenzene

Endpoint summary

Description of key information

Acute oral toxicity: 

Acute oral toxicity dose (LD50) for target chemical 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) was considered based on experimental study conducted on rats. The LD50 value was considered to be >2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, 1,2-di(ethenyl)benzene cannot be classified for acute oral toxicity.

Acute Inhalation toxicity:

The acute Inhalation toxicity dose (LC50) for 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) was considered based on experimental studies conducted on rats. The LC50 value was considered to be >351000 mg/m3. The study concluded that the LC50 value is >5 mg/L, for acute inhalation toxicity. Thus, comparing this value with the criteria of CLP regulation, 1,2-di(ethenyl)benzene cannot be classified for acute inhalation toxicity.

Acute Dermal toxicity:

The acute dermal toxicity dose (LD50) for 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) was considered based on experimental study conducted on rabbits, the value was considered to be 7950 mg/kg bw. The study concluded that the LD50 value is >2000 mg/kg bw, for acute dermal toxicity. Thus, comparing this value with the criteria of CLP regulation, 1,2-di(ethenyl)benzene cannot be classified for acute dermal toxicity.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from authoritative database.

Qualifier:

according to guideline

Guideline:

other: As mentioned below

Principles of method if other than guideline:

Acute oral toxicity of 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) in rat.

GLP compliance:

not specified

Test type:

other: not specified

Limit test:

no

Specific details on test material used for the study:

- IUPAC Name: 1,2-di(ethenyl)benzene- Common Name: Divinylbenzene- InChI: 1S/C10H10/c1-3-9-7-5-6-8-10(9)4-2/h3-8H,1-2H2- Smiles: C=Cc1ccccc1C=C- Molecular formula :C10H10- Molecular weight :131.1969 g/mol- Substance type:Organic- Physical state:colorless or pale yellow transparent liquid- Purity:96.2%- Impurities (identity and concentrations):Ethyl vinyl benzene as impurity 3.2 wt%, p-tert-butyl catechol as 1010 ppm and others as 0.6 wt%

Species:

rat

Strain:

Sprague-Dawley

Remarks:

[Crj: CD (SD) IGS, (SPF)]

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS- Source: Charles River Japan.- Age at study initiation: 4 week old- Weight at study initiation: Body weight ranged from 112 to 120 g for males and 95 to 103 g for females.- Fasting period before study: Animals were fasted for about 20 hours from the evening on the day before administration to about 6 hours after the administration and from the time of grouping until about 6 hours after administration.- Housing: stainless steel cages were used to house up to 5 animals per cage and after grouping they were individually raised using a stainless steel cage.- Diet (e.g. ad libitum): free -fed by solid feed, ad libitum.- Water (e.g. ad libitum): drinking water was freely ingested in tap water, ad libitum.- Acclimation period: The obtained animals were subjected to a 5-day quarantine period and then 3 days ofacclimation period.ENVIRONMENTAL CONDITIONS- Temperature (°C): 20 to 24 ° C.- Humidity (%): 40 to 70%- Air changes (per hr): ventilation frequency 12 times / hour- Photoperiod (hrs dark / hrs light): light and dark each for 12 hours (lighting: 6 am to 6 pm).

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

VEHICLE- Amount of vehicle (if gavage): 10 mL/kg

Doses:

0, 500, 1000, 2000 mg/kg

No. of animals per sex per dose:

Total = 30 animals (5 male and 5 female per group)

Control animals:

yes

Remarks:

Total = 10 (5 male and 5 female)

Details on study design:

- Duration of observation period following administration: 14 days - Frequency of observations: The general condition and the presence or absence of death were observed once a day until the administration day before administration and 6 hours after administration (30 minutes after administration, 2, 4 and 6 hours after administration), and during the observation period from the day after administration; Weighing: Measurement was made on the administration day and at 1, 3, 7, 10 and 14 days after administration.- Necropsy of survivors performed: yes, at the end of the observation period, necropsy was done after exsanguination of the abdominal aorta from the abdominal aorta under ether anesthesia and then necropsied.

Statistics:

For body weight, average values and standard deviations were calculated for each group. Significant difference test was performed using Dunnett's multiple comparison tests between control group and each administration group.

Preliminary study:

In the preliminary tests using the male rats previously conducted (administration stage: 0, 125, 500, and 2000 mg/kg), the dose was not decreased even when 2000 mg/kg was administered, and the dose decreased, only a low value of body weight was recognized. Therefore, in this study, 2000 mg/kg was set as high dose, and 1000 and 500 mg/kg were set as the common ratio 2 below. As a control, a group to which only the vehicle (corn oil) of the same volume as the administration liquid of the test substance administration group was administered was provided.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: No mortality was observed

Mortality:

No mortality was observed in both sexes.

Clinical signs:

other: In the observation of the general condition, a decline in locomotor activity was observed in 2 to 6 hours after administration in both sexes in the 2000 mg/kg group. Besides, diarrhea was observed in each group including females of the control group, but

Gross pathology:

There was no abnormality in both sexes.

Other findings:

not specified

Interpretation of results:

other: Not classified

Conclusions:

The acute oral toxicity dose (LD50) was considered to be >2000 mg/kg bw, when groups of 5 male and 5 female Sprague-Dawley [Crj: CD (SD) IGS, (SPF)] rats were treated with 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) via oral gavage route.

Executive summary:

The acute oral toxicity study was conducted by using 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) in groups of 5 male and 5 female Sprague-Dawley [Crj: CD (SD) IGS, (SPF)] rats at the dose concentration of0, 500, 1000, 2000 mg/kg bw. The given test chemical (Lot No. SXS2; purity: 96.2%, with ethyl vinyl benzene as impurity 3.2 wt%, p-tert-butyl catechol as 1010 ppm and others as 0.6 wt%) was prepared by dilution with corn oil and administered as 10 mL/kg via oral gavage route. In the preliminary tests using the male rats previously conducted (administration stage: 0, 125, 500, and 2000 mg/kg), the dose was not decreased even when 2000 mg/kg was administered, and the dose decreased, only a low value of body weight was recognized. Therefore, in this study, 2000 mg/kg was set as high dose, and 1000 and 500 mg/kg were set as the common ratio 2 below. As a control, a group to which only the vehicle (corn oil) of the same volume as the administration liquid of the test substance administration group was administered was provided. The general condition and the presence or absence of death were observed once a day until the administration day before administration and 6 hours after administration (30 minutes after administration, 2, 4 and 6 hours after administration), and during the observation period from the day after administration; Weighing: Measurement was made on the administration day and at 1, 3, 7, 10 and 14 days after administration. At the end of the observation period, necropsy was done after exsanguination of the abdominal aorta from the abdominal aorta under ether anesthesia and then necropsied. For body weight, average values and standard deviations were calculated for each group. Significant difference test was performed using Dunnett's multiple comparison tests between control group and each administration group. No mortality was observed in both sexes. In the observation of the general condition, a decline in locomotor activity was observed in 2 to 6 hours after administration in both sexes in the 2000 mg/kg group. Besides, diarrhea was observed in each group including females of the control group, but it was considered to be based on corn oil used as a medium. In the 500 mg/kg group, low body weight was observed on both the males and females one day after administration. In the 1000 mg/kg group, low body weight was observed in both sexes on days 1 and 3 after administration. In the 2000 mg/kg group, low body weight was observed on males in 1 to 10 days after administration and in females on 1 and 3 days after administration. There was no abnormality in both sexes. Therefore, the LD50 value was considered to be >2000 mg/kg bw, when groups of 5 male and 5 female Sprague-Dawley [Crj: CD (SD) IGS, (SPF)] rats were treated with 1,2-di(ethenyl)benzene via oral gavage route.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

Data is Klimisch 2 and from authoritative database.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from publication.

Qualifier:

according to guideline

Guideline:

other: As mentioned below

Principles of method if other than guideline:

Acute inhalation toxicity of 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) in rat.

GLP compliance:

not specified

Test type:

other: not specified

Limit test:

no

Specific details on test material used for the study:

- IUPAC Name: 1,2-di(ethenyl)benzene- Common Name: Divinylbenzene- InChI: 1S/C10H10/c1-3-9-7-5-6-8-10(9)4-2/h3-8H,1-2H2- Smiles: C=Cc1ccccc1C=C- Molecular formula:C10H10- Molecular weight :131.1969 g/mol- Substance type:Organic- Physical state:liquid

Species:

rat

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

not specified

Route of administration:

inhalation

Type of inhalation exposure:

not specified

Vehicle:

not specified

Remark on MMAD/GSD:

not specified

Details on inhalation exposure:

not specified

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

7 h

Remarks on duration:

not specified

Concentrations:

351 ppm (351000 mg/m3)

No. of animals per sex per dose:

not specified

Control animals:

not specified

Details on study design:

not specified

Statistics:

not specified

Preliminary study:

not specified

Sex:

not specified

Dose descriptor:

LC50

Effect level:

> 351 000 mg/m³ air

Based on:

test mat.

Exp. duration:

7 h

Remarks on result:

other: No mortality was observed

Mortality:

No mortality was observed in treated rats.

Clinical signs:

other: not specified

Body weight:

not specified

Gross pathology:

not specified

Other findings:

not specified

Interpretation of results:

other: Not classified

Conclusions:

The acute inhalation LC50 value was considered to be >351 ppm (>351000 mg/m3), when rats were treated with 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) via inhalation route for 7 hours.

Executive summary:

Acute inhalation toxicity study of 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) was conducted in rats at the dose concentration of 351 ppm (351000 mg/m3). No mortality was observed in treated rats. Therefore, LC50 value was considered to be >351 ppm (>351000 mg/m3), when rats were treated with 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) via inhalation route for 7 hours.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

351 000 mg/m³ air

Quality of whole database:

Data is Klimisch 2 and from publication.

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from authoritative database.

Qualifier:

according to guideline

Guideline:

other: As mentioned below

Principles of method if other than guideline:

Acute dermal toxicity of 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) in rabbit.

GLP compliance:

not specified

Test type:

other: not specified

Limit test:

no

Specific details on test material used for the study:

- IUPAC Name: 1,2-di(ethenyl)benzene- Common Name: Divinylbenzene- InChI: 1S/C10H10/c1-3-9-7-5-6-8-10(9)4-2/h3-8H,1-2H2- Smiles: C=Cc1ccccc1C=C- Molecular formula :C10H10- Molecular weight :131.1969 g/mol- Substance type:Organic- Physical state:Liquid, colourless- Purity: DVB mixture (55% DVB and 40% ethylvinylbenzene)

Species:

rabbit

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

not specified

Type of coverage:

occlusive

Vehicle:

not specified

Details on dermal exposure:

not specified

Duration of exposure:

24 hour

Doses:

4000 and 7950 mg/kg bw

No. of animals per sex per dose:

not specified

Control animals:

not specified

Details on study design:

- Other examinations performed: Animals were observed for mortality.

Statistics:

not specified

Preliminary study:

not specified

Sex:

not specified

Dose descriptor:

LD50

Effect level:

7 950 mg/kg bw

Based on:

test mat.

Mortality:

Delayed deaths after 3 days.

Clinical signs:

other: not specified

Gross pathology:

not specified

Other findings:

not specified

Interpretation of results:

other: Not classified

Conclusions:

The acute dermal LD50 value was considered to be 7950 mg/kg bw, when rabbits were treated with 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) by dermal application occlusively for 24 hour exposure period.

Executive summary:

Acute dermal toxicity study of 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) was conducted in rabbits at the dose concentration of 4000 and 7950 mg/kg bw by dermal occlusive application for 24 hour. Animals were observed for mortality. The animals tolerated doses of approx. 4000 mg/kg bw. Delayed deaths after 3 days were observed. Hence, LD50 value was considered to be 7950 mg/kg bw, when rabbits were treated with 1,2-di(ethenyl)benzene by dermal application occlusively for 24 hour exposure period.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

7 950 mg/kg bw

Quality of whole database:

Data is Klimisch 2 and from authoritative database.

Additional information

Acute oral toxicity:

In different experimental studies, 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) has been investigated for acute oral toxicity to a greater or lesser extent. Often are the studies based on in-vivo experiments in rodents, i.e. most commonly in rats for 1,2-di(ethenyl)benzene. The studies are summarized as below –

The experimental study conducted on rats and mentioned in authoritative database for the target chemical 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) was designed and conducted to determine acute oral toxicity. The study was conducted in groups of 5 male and 5 female Sprague-Dawley [Crj: CD (SD) IGS, (SPF)] rats at the dose concentration of 0, 500, 1000, 2000 mg/kg bw. The given test chemical (Lot No. SXS2; purity: 96.2%, with ethyl vinyl benzene as impurity 3.2 wt%, p-tert-butyl catechol as 1010 ppm and others as 0.6 wt %) was prepared by dilution with corn oil and administered as 10 mL/kg via oral gavage route. In the preliminary tests using the male rats previously conducted (administration stage: 0, 125, 500, and 2000 mg/kg), the dose was not decreased even when 2000 mg/kg was administered, and the dose decreased, only a low value of body weight was recognized. Therefore, in this study, 2000 mg/kg was set as high dose, and 1000 and 500 mg/kg were set as the common ratio 2 below. As a control, a group to which only the vehicle (corn oil) of the same volume as the administration liquid of the test substance administration group was administered was provided. The general condition and the presence or absence of death were observed once a day until the administration day before administration and 6 hours after administration (30 minutes after administration, 2, 4 and 6 hours after administration), and during the observation period from the day after administration; Weighing: Measurement was made on the administration day and at 1, 3, 7, 10 and 14 days after administration. At the end of the observation period, necropsy was done after exsanguination of the abdominal aorta from the abdominal aorta under ether anesthesia and then necropsied. For body weight, average values and standard deviations were calculated for each group. Significant difference test was performed using Dunnett's multiple comparison tests between control group and each administration group. No mortality was observed in both sexes. In the observation of the general condition, a decline in locomotor activity was observed in 2 to 6 hours after administration in both sexes in the 2000 mg/kg group. Besides, diarrhea was observed in each group including females of the control group, but it was considered to be based on corn oil used as a medium. In the 500 mg/kg group, low body weight was observed on both the males and females one day after administration. In the 1000 mg/kg group, low body weight was observed in both sexes on days 1 and 3 after administration. In the 2000 mg/kg group, low body weight was observed on males in 1 to 10 days after administration and in females on 1 and 3 days after administration. There was no abnormality in both sexes. Therefore, the LD50 value was considered to be >2000 mg/kg bw, when groups of 5 male and 5 female Sprague-Dawley [Crj: CD (SD) IGS, (SPF)] rats were treated with 1,2-di(ethenyl)benzene via oral gavage route.

The above experimental study is supported with the study conducted on rats and mentioned in peer-reviewed journal, authoritative database and secondary source for the target chemical 1,2-di(ethenyl)benzene (CAS no: 1321-74-0). The acute oral toxicity study was conducted in male and female rats at the dose concentration of 4100 and 4640 mg/kg bw. 50% mortality was observed in treated rats. Therefore, LD50 value was considered to be 4100 mg/kg bw in female and 4640 mg/kg bw in male, when male and female rats were treated with 1,2-di(ethenyl)benzene via oral route.

These studies are supported with the study mentioned in authoritative database and conducted in rats for the target chemical 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) at the dose concentration of 630 and 2155 mg/kg bw. Animals were observed for mortality and clinical signs. 50% mortality was observed in treated rats. At 630 mg/kg bw, CNS depression and systemic effects were observed. Hence, LD50 value was considered to be 2155 mg/kg bw, when rats were treated with 1,2-di(ethenyl)benzene via oral route.

All these studies are further supported with the study mentioned in secondary source for the target chemical 1,2-di(ethenyl)benzene (CAS no: 1321-74-0). Acute oral toxicity study was conducted in rats at the dose concentration of 5000 mg/kg bw. 50% mortality was observed in treated rats. Therefore, LD50 value was considered to be 5000 mg/kg bw, when rats were treated with 1,2-di(ethenyl)benzene via oral route.

Thus, based on the above summarised studies on 1,2-di(ethenyl)benzene (CAS no: 1321-74-0), it can be concluded that LD50 value is >2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, 1,2-di(ethenyl)benzene cannot be classified for acute oral toxicity.

Acute Inhalation Toxicity:

In different experimental studies, 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) has been investigated for acute inhalation toxicity to a greater or lesser extent. Often are the studies based on in-vivo experiments in rodents, i.e. most commonly in rats for 1,2-di(ethenyl)benzene along with the studies available for the structurally an functionally similar read across substances. The studies are summarized as below –

The experimental study conducted on rats and mentioned in publication and secondary source for the target chemical 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) was designed to determine acute inhalation toxicity dose. The study was conducted in rats at the dose concentration of 351 ppm (351000 mg/m3). No mortality was observed in treated rats. Therefore, LC50 value was considered to be >351 ppm (>351000 mg/m3), when rats were treated with 1,2-di(ethenyl)benzene via inhalation route for 7 hours.

The above experimental study is supported with another study mentioned in authoritative database for the target chemical 1,2-di(ethenyl)benzene (CAS no: 1321-74-0). Acute inhalation toxicity study was conducted in rats at the dose concentration of 645 ppm (645000 mg/m3). Animals were observed for mortality and clinical signs. No mortality was observed in treated rats. Toxic effects were not observed in treated rats. Hence, LC50 value was considered to be >645 ppm (>645000 mg/m3), when rats were treated with 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) via inhalation route for 7 hours.

Both the experimental studies are further supported with the data available for the structurally and functionally similar read across chemicals. The studies are as mentioned below:

1. The acute inhalation toxicity study was conducted by using test chemical in mice at the concentration of 10000 mg/m³. Animals were observed for mortality and clinical signs. 50% mortality was observed. Observations were noted such as, changes in spleen, multiple effects in liver, kidney, ureter, and bladder, changes observed in both tubules and glomeruli. Hence, LC50 value was considered to be 10000 mg/m³, when mice were exposed to test chemical via inhalation route for 7 hour exposure.

2. The acute inhalation toxicity study was conducted by using test chemical in mice at the concentration range between 2,000 and 17,000 mg/m³. Animals were observed for mortality and clinical signs. Necropsy was performed. 50% mortality was observed in treated mice at 7570 mg/m³ when exposed for 2 hours. Initially all animals exhibited slight inflammations of the eyes and the respiratory tract as well as agitation, followed by a loss of activity. After exposures to values up to 4,000 mg/m³ these symptoms were reversible after the termination of the exposure. Higher concentrations caused further CNS and neuromuscular symptoms (weak reflexes, unsteady gait, respiratory disorders, and tonic-clonic spasms). The dissection revealed injuries in several organs (vascularisation, bleeding, dystrophic changes). Therefore, LC50 was considered to be 7570 mg/m³, when mice were exposed to test chemical via inhalation by vapour for 2 hour exposure.

Thus, based on the above summarised studies on 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) and it’s structurally and functionally similar read across substances, it can be concluded that LC50 value is >5 mg/L. Thus, comparing this value with the criteria of CLP regulation, 1,2-di(ethenyl)benzene cannot be classified for acute inhalation toxicity.

Acute Dermal Toxicity:

In different experimental studies 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) has been investigated for acute dermal toxicity to a greater or lesser extent. Often are the studies based on in-vivo experiments in rodents, i.e. most commonly in rabbits for 1,2-di(ethenyl)benzene along with the studies available for structurally and functionally similar read across chemicals. The studies are summarized as below -

The experimental study mentioned in authoritative database for the target chemical 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) was designed to determine acute dermal toxicity dose.Thestudy was conducted in rabbits at the dose concentration of 4000 and 7950 mg/kg bw by dermal occlusive application for 24 hour. Animals were observed for mortality. The animals tolerated doses of approx. 4000 mg/kg bw. Delayed deaths after 3 days were observed. Hence, LD50 value was considered to be 7950 mg/kg bw, when rabbits were treated with 1,2-di(ethenyl)benzene by dermal application occlusively for 24 hour exposure period.

The above experimental study is supported with the data available for structurally and functionally similar read across chemical and mentioned in publication and authoritative database. The acute dermal toxicity study of test chemical was conducted in rabbits at the dose concentration of 5000 mg/kg bw. No mortality was observed at 5000 mg/kg bw. Hence, LD50 value was considered to be >5000 mg/kg bw, when rabbits were treated with test chemical by dermal application.

All these studies are further supported with the data available for structurally and functionally similar read across chemical. Acute dermal toxicity study of test chemical was conducted in groups of 2 males and 2 females New Zealand white rabbits at the dose concentration of 500, 1000, 2000, 4000, and 5000 mg/kg bw applied to the backs of rabbits for a single dermal exposure. The skin of 2 rabbits per group was abraded while the skin of the remaining 2 rabbits was left intact. The test substance was applied to the site and remained in contact with the skin for 24 hours during which time the rabbits were restrained in harnesses. An occlusive wrap of dental dam was not used because the test material reacted with the dental dam causing an unknown parameter. Following the 24-hour exposure period, each rabbit was removed from the harness and the unabsorbed test material washed off the skin with a damp towel. All rabbits were observed for dermal irritation, gross signs of systemic toxicity indicative of percutaneous absorption and mortality once daily for the next 14 days following the day of dosing. After the observation period, all rabbits were weighed, sacrificed, and gross necropsies performed for signs of morphologic toxicity. No mortality occurred in any of the rabbits during the study. No signs of systemic toxicity or behavioural changes were noted. Incidental findings of skin changes were observed at the site of application. Slight to moderate erythema and very slight edema were noted in 500 to 4000 mg/kg, and moderate responses occurred in 5000 mg/kg. These skin irritation responses returned to normal during the second week in all groups with the exception of 5000 mg/kg where they persisted throughout the study. Slight fissuring was noted occasionally in 2 rabbits in 500 mg/kg and one rabbit in 1000 mg/kg and was classified as being slight to moderate in the group dosed with 5000 mg of the test substance. A dose-related occurrence of coriaceous skin was observed in most rabbits with slight responses in the four lowest dose levels which returned to normal by the end of the second week of the study. Moderate responses of coriaceous skin were noted in 5000 mg/kg. Atonia and desquamation were also observed in 5000 mg/kg. Hence, LD50 value was considered to be >5000 mg/kg bw, when groups of 2 males and 2 females New Zealand white rabbits were treated with test chemical by dermal application occlusively for 24 hours.

Thus, based on the above summarised studies on 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) and it’s structurally and functionally similar read across substances, it can be concluded that LD50 value is >2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, 1,2-di(ethenyl)benzene cannot be classified for acute dermal toxicity.

Justification for classification or non-classification

Based on the above experimental studies on 1,2-di(ethenyl)benzene (CAS no: 1321-74-0) and it’s structurally and functionally similar read across substances, it can be concluded that LD50 value is >2000 mg/kg bw, for acute oral and dermal toxicity; and LC50 value is >5 mg/L, for acute inhalation toxicity. Thus, comparing these values with the criteria of CLP regulation, 1,2-di(ethenyl)benzene cannot be classified for acute oral, acute dermal and acute inhalation toxicity.