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Administrative data

Description of key information

SMBT was corrosive to rabbit skin (SMBT 45%, Monsanto Co. 1987) and highly irritating and corrosive to cornea (SMBT 50%, Bayer AG 1978).

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records
Reference
Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: acceptable, well-documented study report which meets basic scientific principles
Principles of method if other than guideline:
in vivo skin irritation study
GLP compliance:
yes
Species:
rabbit
Strain:
New Zealand White
Type of coverage:
semiocclusive
Preparation of test site:
other: intact skin
Vehicle:
unchanged (no vehicle)
Controls:
not required
Duration of treatment / exposure:
4 h
Observation period:
7 days
Number of animals:
6
Irritation parameter:
overall irritation score
Basis:
mean
Time point:
other: 24, 48, 72 h
Score:
8
Max. score:
8
Reversibility:
not reversible
Remarks on result:
other: corrosive, 7 days (injury in depth)
Other effects:
corrosive after 7 days (cratering - injury in depth)

An erythema score of 4 and an edema score of 4 was found 1h, 24h, 48h and 72h in all rabbits after patch removal. After 168 hours reading/scoring was judged as corrosive with cratering and injury in depth.

Interpretation of results:
corrosive
Remarks:
Migrated information
Executive summary:

Six New Zealand rabbits were applied 0.5 ml of undiluted sodium-mercaptobenzothiazole on the intact skin under semi-occlusive conditions for 4 hours. Skin reactions (erythema and edema) were scored according to Draize 1h, 24 h, 48h, 72 h and 168 h following patch removal.

An erythema score of 4 and an edema score of 4 was found 1h, 24h, 48h and 72h in all rabbits after patch removal. After 168 hours reading/scoring was judged as corrosive with cratering and injury in depth.

Therefor a classification as corrosive to skin (R34 causes burns) according to the classification criteria 67/548/EWG and regulation no. 1272/2008 (GHS) (skin corrosive category 1B, H 314: causes severe skin burns and eye damage) is justified as worst-case consideration because a differentiation between Skin Corrr.1C and Skin Corr.1B is not possible on the basis of the available data.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (corrosive)

Eye irritation

Link to relevant study records
Reference
Endpoint:
eye irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: limited but acceptable documented study report which meets basic scientific principles
Principles of method if other than guideline:
other: in vivo eye irritation study
GLP compliance:
no
Species:
rabbit
Strain:
New Zealand White
Details on test animals or tissues and environmental conditions:
white New Zealand, weight 3 to 4 kg
Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
amount: 100 µl
Duration of treatment / exposure:
7 days
Observation period (in vivo):
7 days
Number of animals or in vitro replicates:
2 per dose
Details on study design:
no further data
Irritation parameter:
other: highly irritating, corrosive to cornea
Remarks on result:
other: highly irritating, corrosive to cornea
Irritant / corrosive response data:
strong irritant
Other effects:
corrosive to the cornea

highly irritating

Interpretation of results:
corrosive
Remarks:
Migrated information
Executive summary:

method: 2 animals received a dose of 100 µl/animal in the conjunctival sac, postexposure period 7 days.

result: strong irritant. corrosive to the cornea

reference: Thyssen/Bayer AG (1978)

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Skin:

The skin irritation potential of the test substance SMBT was evaluated in a skin irritation study with six New Zealand Albino rabbits (Monsanto Co.1984). Undiluted SMBT (45%) was applied under semi-occlusive dressings to the intact rabbit skin of 6 New Zealand albino rabbits for 4 hours. A 7 day observation period followed the test substance application. Skin reactions were observed 1 hour, 24 hours, 48 hours, 72 hours and 168 hours after patch removal.

An erythema score of 4 and an edema score of 4 was found 1h, 24h, 48h and 72h in all rabbits after patch removal. After 168 hours reading/scoring was judged as corrosive with cratering and injury in depth.

Eye:

The eye irritating potential of SMBT (50%) was evaluated in a limited documented study report (Bayer AG 1978). 100 µl of the test substance was applicator into the conjunctival sac. A seven day observation period followed the test substance application. The test substance was classified as highly irritating and corrosive to cornea. A mean iris score of 1, a mean conjunctiva score of 1.66 and a mean chemosis score of 1.33 were determined. For the cornea only the area of the affected eye was reported (mean score 0.33). The effects on the cornea, iris and conjunctiva were persistent up to the end of the observation period (7 days).

This observation is inline with the corrosive potential of SMBT to the rabbit skin discussed above.


Justification for selection of skin irritation / corrosion endpoint:
The most reliable study was used as key study and for classification.

Justification for selection of eye irritation endpoint:
The most reliable study was used as key study and for classification.

Effects on skin irritation/corrosion: corrosive

Effects on eye irritation: corrosive

Justification for classification or non-classification

The test substance SMBT is classified as corrosive to skin (R34 causes burns) according to the classification criteria 67/548/EWG and regulation no. 1272/2008 (GHS) (skin corrosive category 1B, H 314: causes severe skin burns and eye damage) as a worst-case consideration because a differentiation between Skin Corr.1C and Skin Corr.1B is not possible on the basis of the available data.

The test substance is classified as corrosive to the skin, and therefore a serious risk to eyes is regarded as implicit.