Carbon disulphide

Endpoint summary

Description of key information

See discussion below

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to: OECD Guideline for the Testing of Chemicals, Draft Proposal for a New Guideline, In Vitro Skin Irritation: Reconstructed Human Epidermis (RhE) Test Method, 11 December 2009, Vers. 4.

Qualifier:

according to guideline

Guideline:

other: OECD Guideline for the Testing of Chemicals, Draft Proposal for a New Guideline, In Vitro Skin Irritation: Reconstructed Human Epidermis (RhE) Test Method, 11 December 2009, Vers. 4.

GLP compliance:

yes (incl. QA statement)

Type of coverage:

other: in vitro testing

Amount / concentration applied:

Application volume: 15 µL per skin tissue
Test concentration: undiluted

Duration of treatment / exposure:

15 minutes treatment followed by 42 hours further incubation without test item

Details on study design:

One experiment was performed. Three skin tissues (EpiSkin TM Tissues) were treated with each 15 µL of the undiluted test item. The tissues were exposed to the test item for 15 minutes. Afterwards the test item was washed off the tissues and they were incubated for further 42 hours. The evaluation was done via MTT conversion.
Negative control: deionised water (15 µL applied to each of the triplicate of tissues)
Positive control: 5% SLS (Sodium lauryl sulphate) solution in deionised water (15 µL applied to each of the triplicate of tissues)

Irritation / corrosion parameter:

other: relative absorbance value (%)

Value:

67

Vehicle controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other:

Remarks:

all 3 tissues. Time point: 15 min. Remarks: see below for details

Other effects / acceptance of results:

After treatment with carbon disulfide the relative absorbance values were decreased to 67.0%. This value is well above the threshold for irritancy of 50%. Therefore, the test item is not considered to possess an irritant potential.

Table 1: Results after treatment with carbon disulfide

 

Dose group	Treatment Interval	Absorbance 570 nm Tissue 1*	Absorbance 570 nm Tissue 2*	Absorbance 570 nm Tissue 3*	Mean Absorbance of 3 Tissues	Standard Deviation	Rel. Absorbance [% of Negative Control]**
Negative Control	15 min	0.667	0.687	0.662	0.672	2.0	100.0
Positive Control	15 min	0.341	0.176	0.294	0.270	12.6	40.2
Carbon disulfide	15 min	0.460	0.498	0.393	0.450	7.9	67.0

*       Mean of three replicate wells after blank correction
**      relative absorbance [rounded values]

Optical evaluation of the MTT-reducing capacity of the test item after 1 hour incubation with MTT-reagent did not show blue colour.

Interpretation of results:

GHS criteria not met

Remarks:

Migrated information Criteria used for interpretation of results: OECD GHS

Conclusions:

In conclusion, it can be stated that in this study and under the experimental conditions reported, the test item carbon disulfide is non irritant to skin.

Executive summary:

This in vitro study was performed to assess the irritation potential of Carbon disulfide by means of the Human Skin Model Test. Three tissues of the human skin model EpiSkin™ were treated with the test item, the negative or the positive control for 15 minutes. 15 µL of the test item were applied to each tissue, spread to match the tissue size. The test item, the positive and negative controls were washed off the skin tissues after 15 minutes treatment. After further incubation for about 42 hours the tissues were treated with the MTT solution for 3 hours following approximately 70 hours extraction of the colorant from the cells. The amount of extracted colorant wasdetermined photometrically at 570 nm. 15 µL of either the negative control (deionised water) or the positive control (5% Sodium lauryl sulfate) were applied to each tissue. After treatment with the negative control the absorbance values were well above the required acceptability criterion of mean 0.6≤OD≤1.5 for the15 minutestreatment interval thus showing the quality of the tissues. Treatment with the positive control induced a decrease in the relative absorbance as compared to the negative control to 40.2%. The standard deviations between the % variabilities of the test item, the positive and negative controls were below 8% (threshold of the "OECD Guideline for the Testing of Chemicals, Draft Proposal for a New Guideline,In Vitro Skin Irritation": 18%), thus ensuring the validity of the study. After treatment with the test item Carbon disulfide the relative absorbance values were decreased to 67.0%. This value is well above the threshold for irritancy of 50%. Therefore, the test item is not considered to possess an irritant potential.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to: OECD Guideline for Testing of Chemicals 437: Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants (September, 2009).

Qualifier:

according to guideline

Guideline:

other: OECD Guideline for Testing of Chemicals 437: Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants (September, 2009).

GLP compliance:

yes (incl. QA statement)

Amount / concentration applied:

0.75 mL of the undiluted liquid test item were applied to the isolated corneas

Duration of treatment / exposure:

The corneas were exposed to the test item for 10 minutes

Details on study design:

Corneas were treated with the undiluted test item for 10 minutes. After treatment the test item was washed off the corneas and they were further incubated for 2 hours. The opacity of the corneas was determined after the two hours incubation. The change in permeability of the corneas was determined after 90 minutes treatment with fluorescein solution.

Irritation parameter:

cornea opacity score

Value:

0.37

Remarks on result:

other: see below for details

Other effects / acceptance of results:

The test item Carbon disulfide did not cause any opacity or permeability of the corneae compared with the results of the negative control. The calculated mean in vitro score was 0.37 and therefore, the test item was classified as non eye irritant.

Results after 10 Minutes Incubation Time

Test Group	Opacity value = Difference (t130-t0) of Opacity		Permeability at 490 nm (OD490)^*		In vitro score	Mean in vitro score	Proposed in vitro irritation Scale
		Mean		Mean
Negative Control	- 1	- 0.33	0.049	0.047	- 0.27	0.38	Non eye irritant
	0		0.047		0.71
	0		0.046		0.69
Positive Control	58.33*		0.856*		71.17	77.34	Severe eye irritant
	66.33*		0.885*		79.60
	69.33*		0.794*		81.24
Carbon disulfide	0.33*		0.008*		0.45	0.37	Non eye irritant
	0.33*		0.001*		0.34
	0.33*		- 0.001*		0.31

*corrected values

Interpretation of results:

GHS criteria not met

Conclusions:

In conclusion, it can be stated that in this study and under the experimental conditions reported, the test item Carbon disulfide is not considered to be an eye irritant.

Executive summary:

This in vitro study was performed to assess the corneal irritation and damage potential of carbon disulfide by means of the BCOP assay using fresh bovine corneas. After a first opacity measurement of the fresh bovine corneae (t₀), carbon disulfide, the positive, and the negative controls were applied to corneas and incubated for 10 minutes at 32±2 °C in complete medium. After the incubation phase the test item, the positive, and the negative controls were each rinsed off the corneas and opacity was measured again (t₁₀). Further, the corneas were incubated for another 120 minutes at 32±2 °C in complete medium, and opacity was measured a third time (t₁₃₀). After the opacity measurements permeability of the corneas was determined while application of 1 mL of a fluorescein solution for 90 minutes at 32±2 °C in a horizontal position. The liquid coming out was measured spectrophotometrically.

With the negative control (0.9% NaCl solution) neither an increase of opacity nor permeability of the corneae could be observed. The mean in vitro score was calculated as 0.38. The positive control (2-Ethoxyethanol) showed clear opacity and distinctive permeability of the corneae and therefore, is classified as severe eye irritant. The mean in vitro score was calculated as 77.34. The test item carbon disulfide did not cause any opacity or permeability of the corneae compared with the results of the negative control. The calculated mean in vitro score was 0.37 and therefore, the test item was classified as non eye irritant.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin irritation

One in vitro study was performed to assess the corrosive potential of carbon disulfide by means of the Human Skin Model Test. The study was performed according to the OECD Guideline 431. Based on the results CS2 should not considered to be corrosive. One in vitro study was performed to assess the irritation potential of carbon disulfide by means of the Human Skin Model Test. The study was performed according to the OECD Guideline for the Testing of Chemicals, Draft Proposal for a New Guideline (In Vitro Skin Irritation: Reconstructed Human Epidermis (RhE) Test Method, 11 December 2009, Vers. 4). The findings reveal that CS2 is not a skin irritant.

Two non-standard in vivo studies investigating the corrosive/irritating potential of CS2 were identified in the public domain. In the old study of Hueper (1936) small cotton plugs soaked with 2 ml of carbon disulfide were placed into the tip portions of the ears of five rabbits, for 3 -5 consecutive days. The study was performed in order to examine effects on rabbits that have been previously described in viscose rayon workers. The workers were reported to develop serious blisters that evolved to hemorrhagic blisters. Nonetheless, they were not exposed exclusively to CS2, but to a mixture, that consisted of carbon disulfide, sulfuric acid, sodium sulfate, and hydrogen sulfide. The analytical composition was not tested. In the rabbits, early epidermal and subepidermal vesicles were formed in the skin that progressed to ulcers, accompanied by an inflammatory response. The skin manifestations resulting had the clinical and anatomical characteristics of second and third degree chemical burns. However, the documentation was insufficient for assessment. As with the workers, no information on the analytical purity of the test substance is provided and thus, the causative agent of such effects could be an impurity and not CS2 itself. Moreover, exposure time, observation period, strain and sex of the animals are not given. Therefore, the study is deemed not suitable for the evaluation of the irritating properties of CS2.

In the investigation of Chou et al. (2005) topical CS2 exposure exerted a dose-dependent increase in transepidermal water loss (TWEL) and lipid extraction. Cell death in viable epidermis at the highest exposure level, suggests epidermal cell damage. Although the determination of the TWEL is an important endpoint to investigate skin irritation, it does not meet the current classification criteria and hence, CS2 cannot be classified as a skin irritant based exclusively on these results.

For these reasons, the findings of the two in vivo studies described above can be overruled by the two recent, in vitro validated guideline studies. According to this CS2 does not need to be classified as corrosive or irritant to the skin.

 

Eye irritation

Only one study was conducted to assess the eye irritating properties of carbon disulfide. The in vitro study was performed to assess the corneal irritation and damage potential of carbon disulfide by means of the BCOP assay using fresh bovine corneas. The study was performed according to the OECD Guideline 431 and it allows to identify test substances that are corrosive or severe irritants. Carbon disulfide did not cause any opacity or permeability of the corneae. Based on these results CS2 is not corrosive or servere irritant to the eye. No other studies were identified in the public domain.

Respiratory irritation

In an upper respiratory tract irritation study, four rats per group were exposed head-only to analytically confirmed concentrations of CS2 at 1660, 8760, 35100, or 81100 ppm for 10 min. No respiratory rate depression was observed in response to CS2 exposure (Du Pont 1981).

Justification for classification or non-classification

According to the harmonized CLP classification, carbon disulfide is classified as a skin and eye irritant (cat. 2). The above described results, in combination with the human data described in section 7.10, do not indicate a need for classification for skin irritation, eye irritation, or respiratory irritation. However, carbon disulfide is already classified as a skin and eye irritant and on these grounds further in vivo testing cannot be justified. It should also be noted that CS2 is a solvent, and it is well known that solvents are usually mild irritants.