2-ethylimidazole

Endpoint summary

Description of key information

Oral LD50 = 1400 mg/kg bw, mortality was observed (BASF, 1967)
Dermal LD50 > 200 mg/kg bw, no mortality observed (BASF, 1980)
Inhalation LC50 > 0.015 mg/L air (BASF, 1967), LC50 >0.03 mg/L air (BASF, 1980)

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

Study period:

1967-07-04 to 1967-07-05

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP but equivalent to guideline study.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

no

Principles of method if other than guideline:

according to BASF-internal standard

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

other: "US" rats

Sex:

male/female

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 2, 8, 10 and 16% (w/v)

Doses:

200, 800, 1250 and 1600 mg/kg

No. of animals per sex per dose:

10 per dose level

Control animals:

no

Details on study design:

- Duration of observation period following administration: 7 days
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs

Sex:

male/female

Dose descriptor:

LD50

Effect level:

ca. 1 400 mg/kg bw

Based on:

test mat.

Mortality:

200 and 800 mg/kg: no deaths; 1250 mg/kg: 3/10 after 7 days; 1600 mg/kg: 8/10 after 7 days

Clinical signs:

Dyspnea, apathy, abdominal and lateral position

Gross pathology:

Animals that died: all animals with bloody-serous snouts and blurred anus; 1 x diarrhea, 1 x severe distended ectatic stomach, 1 x suspicion of necrosis and hemorrhages of the liver (with putrescence)
Sacrificed animals: nothing abnormal detected

Interpretation of results:

Category 4 based on GHS criteria

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

1 400 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: orientating information about the inhalation hazard

Principles of method if other than guideline:

according to H.F. Smyth et al.: Am. Ind. Hyg. Ass. J. 23, 95-107 (1962)

GLP compliance:

no

Test type:

other: inhalation hazard test

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Wiga, Sulzfeld, Germany
- Diet: ad libitum, Herilan MRH, Eggersmann KG, Rinteln, Germany
- Water: ad libitum

Route of administration:

inhalation

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

The findings of the test depend on the toxicity and volatility of the product.
The product was filled to a height of 5 cm in a fritted glass flask, which had been placed in a water bath maintained at 20°C. A flow of air of 200 liter/hour was conducted through the product. The atmosphere enriched with the possibly volatile components of the test substance in this way was passed through a glass distributor to glass inhalation chambers (tubes) in which one rat had been placed in each case. The exposure periods were 3, 10 and 30 minutes and 1, 3 and 7 hours. The time of exposure was determined at which all animals survived.

Analytical verification of test atmosphere concentrations:

no

Duration of exposure:

7 h

Concentrations:

mean concentration: 0.03 mg/L

No. of animals per sex per dose:

12

Control animals:

no

Details on study design:

The post-exposure observation period was 14 days.
The signs of toxicity and mortality of the test animals were recorded. The animals that died or those sacrificed with carbon dioxide at the end of the post-exposure observation period were subjected to a gross-pathological examination.

Sex:

male/female

Dose descriptor:

LC0

Effect level:

0.03 mg/L air (nominal)

Based on:

test mat.

Exp. duration:

7 h

Mortality:

None

Clinical signs:

other: None

Gross pathology:

Sacrificed animals: organs: nothing abnormal detected

Interpretation of results:

other: The inhalation of a saturated vapor-air-mixture represents an unlikely acute hazard.

Endpoint conclusion

Quality of whole database:

No guideline study, only orientating information about the inhalation hazard is given.

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1980

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Scientifically acceptable study report. Basic information is given. Only tested up to 200 mg/kg

Qualifier:

no guideline followed

Principles of method if other than guideline:

according to BASF-internal standard and DOT guidelines

GLP compliance:

no

Test type:

standard acute method

Limit test:

yes

Species:

rabbit

Strain:

Vienna White

Sex:

male/female

Details on test animals or test system and environmental conditions:

Mean weight for male animals 2.9 kg, female animals: 2.9 kg
The animals received Ssniff K standard diet for rabbits and guinea pigs supplied by INTERMAST GMBH, Soest, FRG, and water ad libitum.
TEST ANIMALS
- Source: Breeding facility M. Gaukler, 6050 Offenbach, Germany
- Weight at study initiation: mean weight 2.9 kg for males and females
- Diet: ad libitum (Ssniff K, standard diet, INTERMAST GMBH, Soest, Germany)
- Water: ad libitum

Type of coverage:

occlusive

Vehicle:

water

Details on dermal exposure:

TEST SITE
- Area of exposure: back and flank
- coverage: 50 cm2
- Type of wrap if used: inert foil fixed with an adhesive tape

REMOVAL OF TEST SUBSTANCE
- Washing (if done): with warm water or a mixture of water and lutrol
- Time after start of exposure: 24 hours

TEST MATERIAL
- Concentration: 50 % aqueous solution
- For solids, paste formed: no

Duration of exposure:

24 hours

Doses:

200 mg/kg

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 8 days
- Frequency of observations and weighing: after 1, 24, 48 h and on Day 8
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 200 mg/kg bw

Based on:

test mat.

Mortality:

None

Clinical signs:

Signs of systemic toxicity: none
Signs of local irritation: initial slight reddening, reversible within 8 days

Body weight:

Not observed

Gross pathology:

No substance-related organ findings

Conclusions:

The acute dermal toxicity of the test substance in Vienna white rabbits was determined. The product was applied as a 50% aqueous test substance preparation by single dose of 200 mg/kg for 24 hours on clipped areas (about 50 cm2) of the back and flanks. The determination of the LD50 was based on the DOT guidelines, but no exact LD50 was established.

Additional information

Acute oral toxicity:
In an acute oral toxicity study, a single oral dose of the test substance at dose levels of 200, 800, 1250 and 1600 mg/kg bw (BASF, 1967) was administered to "US" rat (5/sex/group).

Animals were then observed for 7 days. No mortality was observed up to a dose of 800 mg/kg bw. After 7 days three out of ten animals died at 1250 mg/kg bw and eight out of ten died at the highest tested dose. Animals showed dyspnea, apathy and abdominal and lateral position. All deceased animals showed a bloody-serous snout and blurred anus. Diarrhea, severe distended ectatic stomach and suspicion of necrosis and hemorrhages of the liver were observed each in one animal. The sacrificed animals did not show any gross internal lesions.
An approximate LD50 of 1400 mg/kg bw was reported.

Acute inhalation toxicity:
In an acute inhalation toxicity study according to H.F. Smyth et al.: Am Ind. Hyg. Ass. J. 23, 95 -107 (1962), groups of Spargue-Dawley rats (12/sex) were tested at the technical maximal attainable concentration. The mean concentration was 0.03 mg/L air. The exposure periods were 3, 10 and 30 minutes and 1, 3 and 7 hours. The time of exposure was determined at which all animals survived: After 7 hours of exposure tno animals died. Animals then were observed for 14 days (BASF AG, 1980).

In an acute inhalation toxicity study according to BASF-internal standard (BASF, 1967), groups of 12 rats per sex were exposed to an at 20 °C with dust enriched atmosphere of the test substance (concentration: 0.015 mg/L air) for 8 hours. After the exposure time no animals have died and no abnormalities was observed. One animal showed a chronic bronchitis.

Both acute inhalation toxicity studies were not performed according to an OECD Guideline. Conclusions on the acute inhalation toxicity are not possible because the data provided do not allow the calculation of an LC50. But based on the study results it can be concluded that the LC50 of the test substance is > 0.03 mg/L air and the inhalation of a saturated vapor-air mixture represents an unlikely acute hazard..

Acute dermal toxicity:
In an acute dermal toxicity study, groups of Vienna White rabbits (5/sex) were dermally exposed to the test substance as a 50% aqueous test substance preparation by single dose of 200 mg/kg for 24 hours on clipped areas (about 500 cm²) of the back and flanks. Animals then were observed for 8 days. No mortality occurred within 8 days and a LD50 greater than 200 mg/kg was determined.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008
The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008 (CLP). As a result the substance is considered to be classified for acute oral toxicity under Regulation (EC) No 1272/2008, as amended for the sixth time in Regulation (EC) No 605/2014 as follows: acute toxicity: cat. 4, H302, harmful if swallowed.

Dangerous Substance Directive (67/548/EEC)
The available studies are considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance is considered to be classified for acute oral toxicity under Directive 67/548/EEC, as amended for the 31st time in Directive 2009/2/EG as follows: R22, harmful if swallowed.