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REACH

6,6'-di-tert-butyl-2,2'-thiodi-p-cresol

EC number: 202-009-7 | CAS number: 90-66-4

Life Cycle description
Uses advised against

Toxicological information

Endpoint summary

Administrative data

Description of key information

Acute Toxicity: Oral

LD50 value > 2000 mg/kg bw in female Crl:WI rats.

Acute Toxicity: Dermal

LD50 value >2000 mg/kg bw in male/female Crl:WI rats.

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:

28 March 2017 to 12 April 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Version / remarks:

OECD Guidelines for Testing of Chemicals No. 423. Acute Oral Toxicity – Acute Toxic Class Method. Adopted: 17 December 2001

Deviations:

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Version / remarks:

Commission Regulation (EC) NO 440/2008 of 30 May 2008, B.1.tris

Deviations:

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Version / remarks:

EPA Health Effects Test Guidelines (OPPTS 870.1100), United States, EPA 712-C-98-190 (1998)

Deviations:

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Specific details on test material used for the study:

No further details specified in the study report.

Species:

rat

Strain:

Wistar

Remarks:

Crl:WI

Sex:

female

Details on test animals or test system and environmental conditions:

Species and strain: Crl:WI Wistar rats
Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, D-97633 Sulzfeld, Germany
Hygienic level at arrival: SPF
Hygienic level during the study: Standard housing conditions
Number of animals: 6 animals, 3 animals/group
Sex: Female, nulliparous and non-pregnant
Age of animals at dosing: Young healthy adult rats, 8 weeks old
Body weight at treatment: 185 – 202 g
Acclimatization period: 5-6 days

Husbandry
Animal health: Only healthy animals were used for the test. The health status was certified by the staff Veterinarian.
Number of animal room: 522/4
Housing: 3 animals / cage
Cage type: Type II. polypropylene/polycarbonate
Bedding and nesting: “Lignocel” 3/4-S Hygienic Animal Bedding” and “Arbocel crinklets natural” nesting material produced by J. Rettenmaier & Söhne GmbH + Co.KG (D-73494 Rosenberg, Germany) were available to animals during the study.
Copies of the Certificates of Analysis are retained in the archive at CiToxLAB Hungary Ltd.
Lighting period: 12 hours daily, from 6.00 a.m. to 6.00 p.m.
Temperature: 20.4 – 24.4 °C
Relative humidity: 30 – 64 %
Ventilation: 15-20 air exchanges/hour
Enrichment: Animals were housed by group to allow social interaction and with deep wood sawdust bedding to allow digging and other normal rodent activities.
The temperature and relative humidity were recorded twice daily during the acclimatisation period and throughout the study.

Food and Water Supply
Animals received ssniff® SM R/M "Autoclavable complete diet for rats and mice – breeding and maintenance" produced by ssniff Spezialdiäten GmbH, D-59494 Soest Germany (batch number: 484 14771, expiry date: 30 June 2017), ad libitum, and tap water from the municipal supply, as for human consumption from a 500 ml bottle, ad libitum. The food is considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.
Water quality control analysis is performed once every three months and microbiological assessment is performed monthly, by Veszprém County Institute of State Public Health and Medical Officer Service (ÁNTSZ, H-8201 Veszprém, József A. u. 36., Hungary). The quality control results are retained in the archives at CiToxLAB Hungary Ltd.

.Animal Identification
Animals were individually identified using numbers written on the tail with an indelible marker pen. The numbers were given on the basis of CiToxLAB Hungary Ltd.' S Master File, for each animal allocated to the treatment groups. The cages were identified by cards, with information about study code, sex, dose group, cage number and individual animal numbers.

Route of administration:

oral: gavage

Vehicle:

methylcellulose

Details on oral exposure:

Vehicle: 1% methyl cellulose

Components of the vehicle:
Name: Distilled water
Manufacturer: Hungaro-Gal Kft.
Batch number: 802 0117
Expiry date: 23 July 2017

Name: Methyl cellulose
Manufacturer: Shin-Etsu Chemical Co., Ltd.
Batch number: 5115851
Expiry date: 27 November 2018

Formulation
The test item was freshly formulated at a concentration of 200 mg/mL in the vehicle, in the Pharmacy of CiToxLAB Hungary Ltd. on the day of administration. The formulation container was stirred continuously up to finishing the treatment.

Justification of the dose:
The initial dose level was selected by the Study Director to be that which is most likely to produce mortality in some of the dosed animals. In the lack of any preliminary toxicological information, 2000 mg/kg bw was selected to be the starting dose.

Initially, three female animals were treated with 2000 mg/kg bw of the test item. No mortality was observed, therefore further 3 animals were treated at the dose level of 2000 mg/kg bw. As no mortality was observed in this second dose group, further testing was not required according to the test guidelines (OECD 423, Commission Regulation (EC) NO 440/2008 of 30 May 2008, B.1.tris).

Doses:

The initial dose level was selected by the Study Director to be that which is most likely to produce mortality in some of the dosed animals. In the lack of any preliminary toxicological information, 2000 mg/kg bw was selected to be the starting dose.

No. of animals per sex per dose:

Initially, three female animals were treated with 2000 mg/kg bw of the test item. No mortality was observed, therefore further 3 animals were treated at the dose level of 2000 mg/kg bw. As no mortality was observed in this second dose group, further testing was not required.

Control animals:

Details on study design:

Procedure
A single oral gavage administration was followed by a 14-day observation period. On the night before treatment, the animals were fasted. The food but not water was withheld during an overnight period. Animals were weighed just before treatment. The test item was administered by oral gavage in the morning. The food was returned 3 hours after the treatment.

OBSERVATIONS
Clinical Observations
Clinical observations were performed on all animals at 30 minutes, 1, 2, 3, 4 and 6 hours after dosing and daily for 14 days thereafter. Individual observations were performed on the skin, fur, eyes, mucous membranes, respiratory, circulatory, autonomic and central nervous system, somatomotor activity and behaviour pattern.
Particular attention was directed to observation of tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma.
Body Weight Measurement
The body weight was recorded on the day before treatment (Day -1), on the day of the treatment (Day 0) and weekly thereafter.

NECROPSY
Macroscopic examination was performed on all animals. The animals were sacrificed by exsanguination under pentobarbital anaesthesia (Release, 300 mg / kg pentobarbital sodium; Lot number: 106075, Expiry date: 31 July 2018, Produced by: Wirtschaftsgenossenschaft deutscher Tierärzte eG, Germany). After examination of the external appearance, the cranial, thoracic and the abdominal cavities were opened and the organs and the tissues were observed. Macroscopic abnormalities were recorded.

Statistics:

Not required

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

6,6’-di-tert-butyl-2,2’-thiodi-p-cresol did not cause mortality at a dose level of 2000 mg/kg bw.

Clinical signs:

There were no systemic clinical signs noted in any animal throughout the study.

Body weight:

There were no treatment related body weight changes. Body weight gains of 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol treated animals during the study showed no indication of a test item-related effect.

Gross pathology:

There was no evidence of the macroscopic observations at a dose level of 2000 mg/kg bw.

Other findings:

No further findings detailed in the study report.

CLINICAL OBSERVATIONS

DOSE LEVEL: 2000 mg/kg bw, Treatment on Day 0 SEX: FEMALE

Cage No.

Animal Number

Observations

Observation days

Frequency

7-14

30’

7879

Symptom Free

20/20

7880

Symptom Free

20/20

7881

Symptom Free

20/20

7882

Symptom Free

20/20

7883

Symptom Free

20/20

7884

Symptom Free

20/20

Remarks: + = present

h = hour (s) ‘ = minute

Frequency of observation = number of occurrence of observation / total number of observations

BODY WEIGHT DATA

DOSE LEVEL: 2000 mg/kg bw, Treatment on Day 0 SEX: FEMALE

Cage No.	Animal Number	Body weight (g) Days				Body Weight Gain (g)
Cage No.	Animal Number	-1	0	7	14	-1 – 0	0 – 7	7 – 14	-1 – 14
1	7879	219	197	226	239	-22	29	13	20
	7880	212	200	241	257	-12	41	16	45
	7881	212	202	221	229	-10	19	8	17
2	7882	196	185	204	218	-11	19	14	22
	7883	196	190	209	229	-6	19	20	33
	7884	206	200	224	237	-6	24	13	31
Mean:		206.8	195.7	220.8	234.8	-11.5	25.25	14.0	28.0
Standard deviation:		9.3	6.7	13.2	13.2	5.9	8.7	3.9	10.4

NECROPSY FINDINGS

DOSE LEVEL: 2000 mg/kg bw, Treatment on Day 0 SEX: FEMALE

Cage No.	Animal Number	Necropsy Date/ Necropsy Day	External Observations	Internal Observations	Organ/Tissue
1	7879	11 April 2017 Day 14	No external observation recorded	No internal observations recorded	Not applicable
	7880	11 April 2017 Day 14	No external observation recorded	No internal observations recorded	Not applicable
	7881	11 April 2017 Day 14	No external observation recorded	No internal observations recorded	Not applicable
2	7882	12 April 2017 Day 14	No external observation recorded	No internal observations recorded	Not applicable
	7883	12 April 2017 Day 14	No external observation recorded	No internal observations recorded	Not applicable
	7884	12 April 2017 Day 14	No external observation recorded	No internal observations recorded	Not applicable

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study, the acute oral LD50 value of the test item 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol was found to be above 2000 mg/kg bw in female Crl:WI rats.
According the GHS criteria, 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol can be ranked as "Category 5 or Unclassified" for acute oral exposure.

Executive summary:

The single-dose oral toxicity of 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol was performed according to the acute toxic class method (OECD 423 and Commission Regulation (EC) No 440/2008 of 30 May 2008, B.1.tris) in Crl:WI rats.

Two groups of three female Crl:WI rats were treated with the test item at a dose level of 2000 mg/kg bw (Group 1 and Group 2).

A single oral treatment was carried out by gavage for each animal after an overnight food withdrawal. Food was made available again 3 hours after the treatment. The test item was administered formulated in 1% methyl cellulose at a concentration of 200 mg/mL at a dose volume of 10 mL/kg bw.

Initially, three females (Group 1) were treated at a dose level of 2000 mg/kg bw. As no mortality was observed, a confirmatory group (Group 2) was treated at the same dose level. No mortality was observed in the confirmatory group; therefore no further testing was required according to OECD 423 and Commission Regulation (EC) NO 440/2008 of 30 May 2008, B.1.tris.

Clinical observations were performed at 30 minutes, 1, 2, 3, 4 and 6 hours after dosing and daily for 14 days thereafter. Body weight was measured on Days -1, 0 and 7 and 14 (before necropsy). All animals were subjected to a necropsy and a macroscopic examination.

RESULTS

Mortality

6,6’-di-tert-butyl-2,2’-thiodi-p-cresol did not cause mortality at a dose level of 2000 mg/kg bw.

Clinical Observations

There were no systemic clinical signs noted in any animal throughout the study.

Body Weight and Body Weight Gain

Macroscopic Findings

There was no evidence of the macroscopic observations at a dose level of 2000 mg/kg bw.

CONCLUSION

Under the conditions of this study, the acute oral LD50 value of the test item 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol was found to be above 2000 mg/kg bw in female Crl:WI rats.

According the GHS criteria, 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol can be ranked as "Category 5 or Unclassified" for acute oral exposure.

Endpoint conclusion

Endpoint conclusion:: no adverse effect observed
Dose descriptor:: LD50
Value:: 2 000 mg/kg bw
Quality of whole database:: K1 - GLP accredited laboratory study to OECD Guideline 423 and EU Method B.1 tris

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:: no study available

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:

08 August 2017 to 22 August 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

yes

Remarks:

See "Any other information" for details

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Version / remarks:

Commission Regulation (EC) No 440/2008 of 30 May 2008, B.3.Tris

Deviations:

yes

Remarks:

See "Any other information" for details

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Deviations:

yes

Remarks:

See "Any other information" for details

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Specific details on test material used for the study:

No further details specified in the study report.

Species:

rat

Strain:

Wistar

Remarks:

Crl:WI

Sex:

male/female

Details on test animals or test system and environmental conditions:

Species and strain: Crl:WI Wistar rats
Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, D-97633 Sulzfeld, Germany.
Hygienic level at arrival: SPF
Hygienic level during the study: Standard housing conditions
Number of animals: 5 animals/sex
Sex: Male and female, female rats were nulliparous and non-pregnant
Age of animals at dosing: Young adult rats
Body weight at treatment: Between 221 g and 255 g
Acclimatisation period: 5 days

Husbandry
Animal health: Only healthy animals were used for the test. The health status was certified by the staff Veterinarian.
Number of animal room: 242/6
Housing: Individual caging
Cage type: Type II. polypropylene/polycarbonate
Bedding and nesting: “Lignocel 3/4-S Hygienic Animal Bedding” and “Arbocel crinklets natural” nest building material produced by J. Rettenmaier & Söhne GmbH + Co.KG (D-73494 Rosenberg, Germany) was available to animals during the study.
Lighting period: 12 hours daily, from 6.00 a.m. to 6.00 p.m.
Temperature: 21.1 – 28.2 °C
Relative humidity: 32 – 74 %
Ventilation: 15-20 air exchanges/hour
Enrichment: Rodents were housed with deep wood sawdust bedding to allow digging and other normal rodent activities.
The temperature and relative humidity were recorded twice daily during the acclimatisation period and throughout the study.

Food and Water Supply
Animals received ssniff® SM R/M "Autoclavable complete diet for rats and mice – breeding and maintenance" produced by ssniff Spezialdiäten GmbH, D-59494 Soest, Germany (batch number: 262 21592, expiry date: 31 January 2018), ad libitum, and tap water from the municipal supply, as for human consumption from a 500 mL bottle, ad libitum. The food is considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.
Water quality control analysis is performed once every three months and microbiological assessment is performed monthly, by Veszprém County Institute of State Public Health and Medical Officer Service (ÁNTSZ, H-8201 Veszprém, József A. u. 36., Hungary).

Animal Identification
Animals were individually identified using numbers written on the tail with an indelible marker pen. The numbers were given on the basis of CiToxLAB Hungary Ltd.' s Master File, for each animal allocated to the treatment groups. The cages were identified by cards, with information about study code, sex, dose group, cage number and individual animal numbers.

Type of coverage:

semiocclusive

Vehicle:

water

Details on dermal exposure:

Formulation
The test item was administered as a single dose. Sufficient water was used to dampen the test material to ensure good contact with the skin.

Procedure
The back of each animal was shaved (approximately 10% area of the total body surface) approximately 24 hours prior to treatment. The test item was applied as a single dose to the shaved skin and remained in contact with the skin for the 24-hour exposure period. The test material was dampened with sufficient water before application to ensure good contact with the skin. Sterile gauze pads were placed on the skin of rats to cover the test item. These gauze pads were kept in contact with the skin using a patch with adhesive hypoallergenic plaster. The entire trunk of the animal was then wrapped with semi occlusive plastic wrap for 24 hours.
At the end of the exposure period, the area of skin treated with the test item was washed with water of body temperature.

Duration of exposure:

24 hours.

Doses:

A single dermal application was made.

No. of animals per sex per dose:

10 (5 males/5 females)

Control animals:

Details on study design:

Clinical Observations
Clinical observations were performed on the day of treatment at 1 and 5 hours after application of the test item and once each day for 14 days thereafter. Observations included the skin and fur, eyes and mucous membranes, the respiratory, circulatory, autonomic and central nervous system, somatomotor activity and behaviour pattern.
Particular attention was directed to observation of tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma.
Skin Irritation:
Adverse skin reactions at the site of application were recorded daily following the removal of the dressing.

Body Weight Measurement
The body weights were recorded on Day 0 (before test item administration) and on Days 7 and 14 just before necropsy.

NECROPSY
Macroscopic examination was performed on all animals. The animals were sacrificed by exsanguination under pentobarbital anaesthesia (Release, 300 mg/mL pentobarbital sodium; Lot number: 106075, Expiry date: 31 July 2018, Produced by: Wirtschaftsgenossenschaft deutscher Tierärzte eG, Germany). After examination of the external appearance, the cranial, thoracic and the abdominal cavities were opened and the organs and the tissues were observed. Macroscopic abnormalities were recorded.

Statistics:

Not specified.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

6,6’-di-tert-butyl-2,2’-thiodi-p-cresol did not cause mortality at the dose level of 2000 mg/kg bw.

Clinical signs:

There were no systemic clinical signs noted in any animal throughout the study.

Body weight:

Body weight gains of 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol treated animals during the study showed no indication of a test item-related effect.

Gross pathology:

There was no evidence of the macroscopic observations at a dose level of 2000 mg/kg bw.

Other findings:

No local dermal signs were observed after treatment with the test item during the 14 days observation period.

CLINICAL OBSERVATIONS

DOSE LEVEL: 2000 mg/kg bw

SEX: MALE

Cage No.

Animal No.

Observations

Observation days

Frequency

357

Symptom Free

16/16

358

Symptom Free

16/16

359

Symptom Free

16/16

360

Symptom Free

16/16

361

Symptom Free

16/16

DOSE LEVEL: 2000 mg/kg bw

SEX: FEMALE

Cage No.

Animal No.

Observations

Observations days

Frequency

362

Symptom Free

16/16

363

Symptom Free

16/16

364

Symptom Free

16/16

365

Symptom Free

16/16

366

Symptom Free

16/16

Remarks: + = present

h = hour (s) Treatment day = Day 0

Frequency of observation = number of occurrence of observations / total number of observations

BODY WEIGHT DATA

DOSE LEVEL: 2000 mg/kg bw						SEX: MALE
Cage No.	Animal No.	Body weight (g)			Body Weight Gain (g)
		Days			Body Weight Gain (g)
		0	7	14	0-7	7-14	0-14
1	357	233	297	349	64	52	116
2	358	243	285	319	42	34	76
3	359	247	309	366	62	57	119
4	360	229	288	358	59	70	129
5	361	222	289	247	67	58	125
Mean:		234.8	293.6	347.8	58.8	54.25	113.0
Standard deviation:		10.2	9.7	17.8	9.8	13.1	21.3

DOSE LEVEL: 2000 mg/kg bw						SEX: FEMALE
Cage No.	Animal No.	Body weight (g)			Body Weight Gain (g)
		Days			Body Weight Gain (g)
		0	7	14	0-7	7-14	0-14
6	362	225	264	279	39	15	54
7	363	242	261	276	19	15	34
8	364	255	317	338	62	21	83
9	365	221	240	251	19	11	30
10	366	232	252	257	20	5	25
Mean:		235.0	266.8	280.2	31.8	143.4	45.2
Standard deviation:		13.7	29.6	34.5	18.9	5.9	23.8

NECROPSY FINDINGS

DOSE LEVEL: 2000 mg/kg bw					SEX: MALE
Cage No.	Animal No.	Necropsy Date/ Necropsy Day	External Observations	Internal Observations	Organ/ Tissue
1	357	22 August 2017 Day 14	No external observations	No internal observations	Not applicable
2	358	22 August 2017 Day 14	No external observations	No internal observations	Not applicable
3	359	22 August 2017 Day 14	No external observations	No internal observations	Not applicable
4	360	22 August 2017 Day 14	No external observations	No internal observations	Not applicable
5	361	22 August 2017 Day 14	No external observations	No internal observations	Not applicable

DOSE LEVEL: 2000 mg/kg bw					SEX: FEMALE
Cage No.	Animal No.	Necropsy Date/ Necropsy Day	External Observations	Internal Observations	Organ/ Tissue
6	362	22 August 2017 Day 14	No external observations	No internal observations	Not applicable
7	363	22 August 2017 Day 14	No external observations	No internal observations	Not applicable
8	364	22 August 2017 Day 14	No external observations	No internal observations	Not applicable
9	365	22 August 2017 Day 14	No external observations	No internal observations	Not applicable
10	366	22 August 2017 Day 14	No external observations	No internal observations	Not applicable

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study, the acute dermal median lethal dose (LD50 value) of the test item 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol was found to be above 2000 mg/kg bw in male and female Crl:WI rats.
According to the GHS criteria, 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol can be ranked as "Category 5 or Unclassified" for acute dermal exposure.

Executive summary:

An acute dermal toxicity study was performed with test item 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol in Crl:WI rats, in compliance with OECD Guideline No. 402.

A limit test was carried out at 2000 mg/kg body weight (bw) in both sexes (5 rats/sex). The test item was applied as a single dermal 24-hour exposure followed by a 14-day observation period.

Clinical observations were performed on all animals at 1 and 5 hours after dosing and daily for 14 days thereafter. Body weight was measured prior to dosing on Day 0 and on Days 7 and 14. Gross macroscopic examination was performed on all animals at the end of the 2-week observation period (Day 14).

RESULTS

Mortality

6,6’-di-tert-butyl-2,2’-thiodi-p-cresol did not cause mortality at the dose level of 2000 mg/kg bw.

Clinical Observations

There were no systemic clinical signs noted in any animal throughout the study.

Local dermal signs

No local dermal signs were observed after treatment with the test item during the 14 days observation period.

Body weight and body weight gain

Body weight gains of 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol treated animals during the study showed no indication of a test item-related effect.

Macroscopic Findings

There was no evidence of the macroscopic observations at a dose level of 2000 mg/kg bw.

CONCLUSIONS

According to the GHS criteria, 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol can be ranked as "Category 5 or Unclassified" for acute dermal exposure.

Endpoint conclusion

Endpoint conclusion:: no adverse effect observed
Dose descriptor:: LD50
Value:: 2 000 mg/kg bw
Quality of whole database:: K1 - GLP accredited laboratory study to OECD Guideline 402 and EU Method B.3 tris

Additional information

Acute Toxicity: Oral

Two groups of three female Crl:WI rats were treated with the test item at a dose level of 2000 mg/kg bw (Group 1 and Group 2).

RESULTS

Mortality

6,6’-di-tert-butyl-2,2’-thiodi-p-cresol did not cause mortality at a dose level of 2000 mg/kg bw.

Clinical Observations

There were no systemic clinical signs noted in any animal throughout the study.

Body Weight and Body Weight Gain

Macroscopic Findings

There was no evidence of the macroscopic observations at a dose level of 2000 mg/kg bw.

Acute Toxicity: Dermal

An acute dermal toxicity study was performed with test item 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol in Crl:WI rats, in compliance with OECD Guideline No. 402.

A limit test was carried out at 2000 mg/kg body weight (bw) in both sexes (5 rats/sex). The test item was applied as a single dermal 24-hour exposure followed by a 14-day observation period.

RESULTS

Mortality

6,6’-di-tert-butyl-2,2’-thiodi-p-cresol did not cause mortality at the dose level of 2000 mg/kg bw.

Clinical Observations

There were no systemic clinical signs noted in any animal throughout the study.

Local dermal signs

No local dermal signs were observed after treatment with the test item during the 14 days observation period.

Body weight and body weight gain

Body weight gains of 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol treated animals during the study showed no indication of a test item-related effect.

Macroscopic Findings

There was no evidence of the macroscopic observations at a dose level of 2000 mg/kg bw.

Justification for classification or non-classification

Acute Toxicty: Oral

According the GHS criteria, 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol can be ranked as "Category 5 or Unclassified" for acute oral exposure.

Acute Toxicity: Dermal

According to the GHS criteria, 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol can be ranked as "Category 5 or Unclassified" for acute dermal exposure.

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