Sodium methanethiolate

Endpoint summary

Description of key information

The potential of Sodium methanethiolate to induce skin corrosion/irritation was tested in a suitable in vivo studies. Based on the results, the sodium methanethiolate must be considered corrosive to the skin and eye.

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:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

adopted 1992

GLP compliance:

yes

Specific details on test material used for the study:

- Test article name: Sodium methylmercaptide
- CAS NR: 5188-07-8
- Origin: Elf Atochem NA
- Composition: Sodium methylmercaptide: 21.0% solution in water

Species:

rabbit

Strain:

New Zealand White

Type of coverage:

semiocclusive

Preparation of test site:

not specified

Vehicle:

unchanged (no vehicle)

Controls:

not specified

Amount / concentration applied:

0.5 mL

Duration of treatment / exposure:

3 minutes

Observation period:

1 and 24 hours

Number of animals:

6

Details on study design:

The potential irritant and/or corrosive effects of Sodium methyl mercaptide were evaluated on the skin of New Zealand White rabbits. Each of six rabbits received a 0.5 mL dose of the test article as a single dermal application. The dose was held in contact with the skin under a semi-occlusive binder for an exposure period of three minutes. Following the exposure periods, the gauze patch and/or binder were removed and the remaining test article was wiped from the skin using gauze moistened with deionized water. Test sites were evaluated for potential in-depth injury immediately following patch removal, one hour following patch removal and 24 hours following patch application.

Irritation parameter:

other: necrosis

Basis:

other: all animals

Time point:

other: 1 hour

Reversibility:

not reversible

Remarks on result:

other:

Remarks:

necrosis (grades 1-4) and blanching (grades 3-4) on 6/6 test sites

Irritation parameter:

other: necrosis

Basis:

other: 5 animals

Time point:

24 h

Reversibility:

not reversible

Remarks on result:

other:

Remarks:

necrosis (grades 1-2) was noted on 5/6 test sites, blanching (grades 2-4) and eschar (grades 1-3) were noted on 6/6 test sites

Irritant / corrosive response data:

Exposure to the test article for a three-minute exposure period produced necrosis (grades 1-4) and blanching (grades 3-4) on 6/6 test sites by the one hour scoring interval. At the 24 hour scoring interval, necrosis (grades 1-2) was noted on 5/6 test sites and blanching (grades 2-4) and eschar (grades 1-3) were noted on 6/6 test sites.

Interpretation of results:

Category 1A (corrosive) based on GHS criteria

Conclusions:

In this study under the given conditions the test item showed corrosive effects. Thus, the substance meets the criteria of the CLP Regulation 1272/2008 for being classified as Skin Corr. 1A.

Executive summary:

In a primary dermal irritation study (OECD TG 404) 6 New Zealand white rabbits were dermally exposed to 0.5 mL test item (21.0% solution in water) for 3 minutes under semi-occlusive conditions. Irritation was scored after 1 and 24 hours. Exposure to the test item for a three-minute exposure period produced necrosis (grades 1-4) and blanching (grades 3-4) on 6/6 test sites after 1 hour. At the 24 hour observation time point, necrosis (grades 1-2) was noted on 5/6 test sites and blanching (grades 2-4) and eschar (grades 1-3) were noted on 6/6 test sites.

Based on the results, the test substance is considered to be corrosive to the skin of the rabbit after a three-minute exposure period. In accordance with CLP Regulation 1272/2008 classification as Skin Corr. 1A, H314 is warranted.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is classified as skin corrosion, leading to classification as serious eye damage (Category 1)

Endpoint conclusion

Endpoint conclusion:

no study available

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

In the OECD SIDS dossier for Sodium methanethiolate (SIAM 27, October 2008) several studies are published to assess the potential of the target substance to induce skin and eye irritation/corrosion.

In a primary dermal irritation study (OECD TG 404) 6 New Zealand white rabbits (sex not specified) were dermally exposed to 0.5 mL of the test item Sodium methanethiolate (21.0% solution in water) for 3 minutes under semi-occlusive conditions. Irritation was scored at 1 and 24 hours. Exposure to the test item for a three-minute exposure period produced necrosis (grades 1-4) and blanching (grades 3-4) on 6/6 test sites by the one-hour observation period. At the 24-hour observation period, necrosis (grades 1-2) was noted on 5/6 test sites and blanching (grades 2-4) and eschar (grades 1-3) were noted on 6/6 test sites. Based on the results, the test substance is considered to be corrosive to the skin of the rabbit after a three-minute exposure period.

 

Two additional primary skin irritation studies were available for Sodium methanethiolate in rabbits according to the OECD TG 404. In one study, a 19.9% solution of Sodium methanethiolate applied to the skin of one rabbit for four hours under semi-occlusive conditions induced necrosis signs at the application site of the test substance by the one and twenty-four-hour observation periods. In another study, a 19.6% solution of Sodium methanethiolate in methanol applied to the skin of one rabbit for four hours under semi-occlusive conditions (without removal or washing) was also found to be corrosive.

Based on the results, the test item must be considered corrosive to the skin and eye and in accordance with CLP Regulation 1272/2008 classification as Skin Corr. 1A, H314 and Eye Dam. 1, H318 is warranted.

Justification for classification or non-classification

Based on the available data and in accordance with CLP Regulation 1272/2008 Sodium methanethiolate does warrant classification as Skin Corr. 1A, H314 and Eye Dam.1, H318.