5H-1,2-oxathiole 2,2-dioxide

Endpoint summary

Description of key information

Skin Corrosion: Not corrosive (OECD 431/GLP)

Skin Irritation: Not irritating (OECD 439/GLP)

Serious eye damage/eye irritation: Irritating (OECD 437/GLP; OECD 431/439 GLP; Weight of Evidence)

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18/06/2019 - 06/09/2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

Version / remarks:

2019

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Shijiazhuang Suntec-chem Co.,Ltd; 190403
- Expiration date of the lot/batch: Apr 10, 2020
- Purity: 99.92%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed.
- Stability under test conditions: During the study the test item sample was stored in in original containers in a dry place.

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: reconstructed human epidermal model EpiDerm™ (EPI-200-SCT)
- Tissue batch number(s): No. 30804, kit C

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: tissues were topically exposed to the test chemicals for 3 (room temperature) and 60 minutes at culture conditions (37±1°C, 5±1 % CO2, humidified).
- Temperature of post-treatment incubation (if applicable): 37±1°C, 5±1 % CO2, humidified.

REMOVAL OF TEST MATERIAL AND CONTROLS
- Volume and number of washing steps: After exposition, tissues were thoroughly rinsed and blotted to remove the test item/controls.
- Observable damage in the tissue due to washing: None


MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg per mL
- Incubation time: 3 hours
- Spectrophotometer: Libra S22
- Wavelength: 570 nm

CONTROL TISSUES USED IN CASE OF MTT DIRECT/COLOUR INTERFERENCE
1. Functional check for MTT interference was performed as follows: 25 mg of the test item was added to 1 mL MTT medium (red) and incubated in the incubator (37±1°C, 5±1 % CO2, humidified) for 1 hour. At the end of the exposure time, the presence and intensity of the staining (if any) were observed.
2. Functional check for colour interference was performed as follows: 25 mg of the test item was added to 0.3 mL of water for injection and incubated in the incubator (37±1°C, 5±1 % CO2, humidified) for about 1 hour. At the end of the exposure time, the presence and intensity of the staining (if any) were observed. Another 25 mg of the test item was added to 2.0 mL of isopropyl alcohol and incubated at room temperature without shaking for 2 hours and 15 minutes. At the end of the exposure time, the presence and intensity of the staining (if any) were observed.

NUMBER OF REPLICATE TISSUES: Three tissues were used per the test item (C1), three for the the positive (PC) and three for the negative (NC) controls

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than 50%, or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater than or equal to 15%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 mg of the test item with 25 μL of PBS

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL H2O

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL 8N KOH

Duration of treatment / exposure:

3 minutes / 60 minutes

Duration of post-treatment incubation (if applicable):

3 hours

Number of replicates:

3 per group

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

test item-3 minutes treatment

Value:

106.6

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

test item-60 minutes treatment

Value:

92.5

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

positive control-3 min

Value:

6.2

Negative controls validity:

valid

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

positive control-60 min

Value:

6.8

Negative controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- Direct-MTT reduction: The test item did not reduce MTT directly
- Colour interference with MTT: The colour of the test material did not interfere with the endpoint

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The assay meets the acceptance criterion - OD570 of the NC tissues was 1.776 (3 min) and 1.712 (60 min) which is ≥ 0.8 and ≤ 2.8.
- Acceptance criteria met for positive control: Viability of tissues treated with 8N KOH after 60 minutes treatment was 6.8% which is ＜15%.
- Coefficient of variation: CV was higher than 0.3 in one case (see Table 1) but this was an acceptable deviation.

Table 1:MTT test results

Time	Treatment		OD570			Mean	SD	CV	% NC
			Tissues
			1	2	3
3 min	NC	water	1.64	1.847	1.842	1.776	0.096	0.054	100.0
	C1	152/19	1.877	1.907	1.898	1.894	0.013	0.007	106.6
	PC	8N KOH	0.115	0.109	0.108	0.111	0.003	0.028	6.2
60 min	NC	water	1.737	1.715	1.685	1.712	0.021	0.012	100.0
	C1	152/19	1.537	1.61	1.606	1.584	0.034	0.021	92.5
	PC	8N KOH	0.079	0.169	0.103	0.117	0.038	0.325	6.8

152/19 = 1,3 Propene Sultone

Interpretation of results:

GHS criteria not met

Remarks:

Not classifed according to CLP

Conclusions:

In the in vitro skin corrosion test using the reconstructed human epidermal model EpiDermTM, the test item 1,3-Propene Sultone was non-corrosive.

Executive summary:

In an in vitro skin corrosion in the human epidermal model EpiDerm (152-19-4AC), reconstructed human epidermis tissue was exposed to 25 mg of 1,3-Propenesultone (99.92%) for 3 and 60 minutes. H2O was used for the negative control and 8N KOH was used for the positive control. After removal of the test substance, the tissues were incubated with MTT for three hours and then extracted with isopropyl alcohol overnight at room temperature with shaking. The OD570 of isopropyl alcohol extracts was measured on a spectrophotometer. Relative cell viability was calculated for each tissue as % of the mean viability of the negative control tissues.

The controls confirmed the validity of the study. The mean absolute OD570 of the three negative control tissues was ≥ 0.8 and ≤ 2.8 [1.776 (3 min) and 1.712 (60 min)]. The mean relative tissue viability (% negative control) of the positive control was < 15% [6.8% (60 min)]. Coefficient of variation (CV) was higher than 0.3 in one case but this was an acceptable deviation. The colour of the test substance did not interfere with the endpoint. The test substance is not directly MTT reducing. The average viability of tissues treated by the test item, 1,3-Propenesultone were higher than the threshold values (50 % and 15% respectively): 106.6 % ≥ 50% after 3 minutes exposure and 92.5% ≥ 15% after 60 minutes exposure. The test item should be regarded as non-corrosive.

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17/07/2019 - 26/08/2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

2019

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Shijiazhuang Suntec-chem Co.,Ltd; 190403
- Expiration date of the lot/batch: Apr 10, 2020
- Purity: 99.92%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed.
- Stability under test conditions: During the study the test item sample was stored in in original containers in a dry place.

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: reconstructed human epidermal model EpiDerm (EPI-200)
- Tissue batch number(s): 30812

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 25 minutes at room temperature and the remaining 35 minutes at culture conditions(37±1°C).

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: Tissues were then thoroughly rinsed with PBS.
- Observable damage in the tissue due to washing: None


MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL
- Incubation time: 180 minutes
- Spectrophotometer: Libra S22
- Wavelength: 570 nm

CONTROL TISSUES USED IN CASE OF MTT DIRECT/COLOUR INTERFERENCE
No complementary experiments were performed, because they were done as a part of the Study No. 152/19/4AC: 1,3-Propene Sultone - In vitro Skin Corrosion Test (EpiDermTM Model); VUOS-CETA, Report No. 19-287, 2019.

NUMBER OF REPLICATE TISSUES: Three tissues were used for the test item, three for the the positive (PC) and three for the negative (NC) controls.

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the test chemical is found to be non-corrosive (e.g., based on TG 430, 431 or 435), and shows tissue viability after exposure and post-treatment incubation is less than or equal (≤) to 50 %
- The test substance is considered to be non-corrosive to skin if the tissue viability after exposure and post-treatment incubation is more than (>) 50 %.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 mg

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 30 μL of PBS

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 30 μL
- Concentration (if solution): 5% SDS (sodium dodecyl sulfate) water solution

Duration of treatment / exposure:

60±1 minutes (25 minutes at room temperature and the remaining 35 minutes at culture conditions)

Duration of post-treatment incubation (if applicable):

42±2 hours

Number of replicates:

3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

test item

Value:

56

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

other:

Remarks:

56±2.734

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

positive control

Value:

2.8

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

other:

Remarks:

2.8±0.106

Other effects / acceptance of results:

- OTHER EFFECTS:
- Direct-MTT reduction & Colour interference with MTT: Complementary experiments performed as a part of the Study No. 152/19/4AC: 1,3-Propene Sultone - In vitro Skin Corrosion Test (EpiDermTM Model); VUOS-CETA, Report No. 19-287, 2019, gave negative results. The test item colour does not influence study results and the test item does not have direct reductive properties, so no correction of MTT test results have to be performed

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The mean OD570 of the NC tissue was 1.776 which meets the acceptance criteria of ≥ 0.8 and ≤ 2.8.
- Acceptance criteria met for positive control: The mean viability of the PC tissues expressed as % of the negative control tissues was 2.8 % which meets the acceptance criterion of ≤ 20 %.
- Acceptance criteria met for variability between replicate measurements:
The SD calculated from individual % tissue viabilities of the 3 identically treated replicates was 0.1 % for the positive control, 4.0 % for negative control and 2.7 % for the test item what is < 18 % in all cases.

Table 1: OD570 values obtained at the MTT test, their averages, standard deviations (%) and relative viabilities

Treatment	OD570	Tissue			Avg	SD	Average viability
		1	2	3			(% NC)
NC	OD	1.874	1.748	1.706	1.776	0.071	100.0
DPBS	%	105.5	98.4	96.1	100	4.019
C1	OD	1.063	0.96	0.96	0.994	0.049	56.0
152/19	%	59.9	54.1	54.1	56	2.734
PC	OD	0.048	0.048	0.052	0.049	0.002	2.8
5% SDS	%	2.7	2.7	2.9	2.8	0.106

 152/19 = 1,3 Propene Sultone

Interpretation of results:

GHS criteria not met

Remarks:

Not classifed according to CLP

Conclusions:

In the in vitro skin irritation test using the reconstructed human epidermal model EpiDerm, the test item 1,3-Propene Sultone is considered a non-irritant to skin.

Executive summary:

In an in vitro skin irritation assay in a human epidermal model EpiDerm (152-19-4AI), reconstructed human epidermis tissue was exposed to 25 mg of 1,3-Propenesultone (99.92%) for 60±1 minutes ( 25 minutes at room temperature and the remaining 35 minutes at culture conditions). DPBS was used for the negative control and 5% SDS was used for the positive control. After removal of the test substance, tissues were post-incubated for 42±2 hours. After three hours incubation with MTT, samples were extracted with isopropyl alcohol for approximately two hours. The OD570 of isopropyl alcohol extracts was measured on a spectrophotometer. Relative cell viability was calculated for each tissue as % of the mean viability of the negative control tissues.

The controls confirmed the validity of the study. The mean absolute OD570 of the three negative control tissues was ≥ 0.8 and ≤ 2.8 (1.776). The mean relative tissue viability (% negative control) of the positive control was ≤ 20% (2.8%). Standard deviation of viability of replicate tissues of all dose groups was < 18% (0.1 % for the positive control, 4.0 % for negative control and 2.7 % for the test item). The colour of the test substance did not interfere with the endpoint. The test substance is not directly MTT reducing. The average viability of tissues treated by the test item, 1,3-Propenesultone, was 56±2.734% of the negative control average value i.e. viability was > 50 %. According to these results, the test substance is non-irritating to skin.

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:

weight of evidence

Study period:

31.07.2019 - 12.08.2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Shijiazhuang Suntec-chem Co.,Ltd.;190403
- Expiration date of the lot/batch: Apr 10, 2020
- Purity: 99.92%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed.

Species:

cattle

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Source: Breeding service CHOVSERVIS a.s., division TORO® Hlavečník, Hradec Králové, Czech Republic
- Characteristics of donor animals (e.g. age, sex, weight): Only healthy animals (12 to 30 months old) considered suitable for entry into the human food chain were used as a source of corneas
- Storage, temperature and transport conditions of ocular tissue (e.g. transport time, transport media and temperature, and other conditions): Keeping the container containing the eyes on ice, adding antibiotics to the HBSS used to store the eyes during transport (e.g., penicillin at 100 IU/mL and streptomycin at 100 μg/mL)
- Time interval prior to initiating testing: typically collected and used on the same day.
- Indication of any existing defects or lesions in ocular tissue samples: The eyes, once they arrive at the laboratory, were carefully examined for defects including scratched, and neovascularisation. Only corneas from eyes free of such defects were used.
- Indication of any antibiotics used: penicillin at 100 IU/mL and streptomycin at 100 μg/mL

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

The test item was applied in delivered form, because the suspension or solution of the test item was not possible to use, using the open chamber method.

Duration of treatment / exposure:

4 hours

Number of animals or in vitro replicates:

3 per group

Details on study design:

SELECTION AND PREPARATION OF CORNEAS: Eyes were collected by slaughterhouse employees. The eyes were enucleated as soon as possible after death. No detergent was used. The eyes, once they arrive at the laboratory, were carefully examined for defects including scratched, and neovascularisation. Only corneas from eyes free of such defects were used.
Corneas free of defects were dissected with a 2 to 3 mm rim of sclera remaining to assist in subsequent handling. Isolated corneas were mounted in specially designed corneal holders that consisted of anterior and posterior compartments, which interfaced with the epithelial and endothelial sides of the cornea, respectively. Both chambers were filled to excess with pre-warmed Eagle's Minimum Essential Medium (EMEM). The device was then equilibrated at 32 ± 1°C for at least one hour in water bath to allow the corneas to equilibrate with the medium and to achieve normal metabolic activity, to the extent possible.

QUALITY CHECK OF THE ISOLATED CORNEAS: The isolated corneas, after achieve normal metabolic activity (inductive incubation at 32 ± 1°C for one hour), were examined again. The corneas that show macroscopic tissue damage (e.g., scratches, pigmentation, neovascularization) or a baseline opacity >7 opacity units were discarded.

NUMBER OF REPLICATES: Each test group (test item, concurrent negative and positive controls) consisted of the three corneas.

NEGATIVE CONTROL USED: 0.9% NaCl solution

POSITIVE CONTROL USED: 20% w/v imidazole in 0.9% NaCl solution

APPLICATION DOSE AND EXPOSURE TIME: Because the test item could not be possible applied by micropipette. The test item (the test item in quantity enough to completely cover the cornea) was applied directly to the epithelial surface of the cornea using the spatula. After dosing, the glass window was replaced on the anterior chamber to recreate a closed system.
Corneas were exposed for 4 hours.

TREATMENT METHOD: open chamber

POST-INCUBATION PERIOD: no.

REMOVAL OF TEST SUBSTANCE
- Number of washing steps after exposure period: After the exposure period, the negative and positive control substances and the test item were removed from the anterior chamber with EMEM (containing phenol red - the effectiveness of rinsing acidic or alkaline materials). The corneas were given a final rinse with EMEM (without phenol red). The EMEM (without phenol red) was used as a final rinse to ensure removal of the phenol red from the anterior chamber prior to the opacity measurement. The anterior chamber was then refilled with fresh EMEM without phenol red.
- POST-EXPOSURE INCUBATION: application of sodium fluorescein (5 mg/ml), incubation 1.5 hour (32 ± 1°C)

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: Corneal opacity (as value of illuminance) was measured quantitatively with the aid of an opacitometer (Opacitometer, Kit OP3,0 – Duratec, Analysertechnik – Germany).
- Corneal permeability: passage of sodium fluorescein dye measured with the aid of UV/VIS spectrophotometry (OD490)

SCORING SYSTEM: In Vitro Irritancy Score (IVIS) = mean opacity value + (15 x mean permeability OD490 value)

DECISION CRITERIA: the decision criteria as indicated in the TG was used.

Irritation parameter:

in vitro irritation score

Run / experiment:

Test item

Value:

33.5

Negative controls validity:

valid

Positive controls validity:

valid

Irritation parameter:

in vitro irritation score

Run / experiment:

negative control

Value:

2.81

Negative controls validity:

valid

Positive controls validity:

valid

Irritation parameter:

in vitro irritation score

Run / experiment:

positive control

Value:

71.95

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: Appearance of corneas was observed before and after application of the test item, negative and positive control (see Table 2 and 3). No macroscopic damage was observed on corneas before application. Corneal opacity was observed on the corneas treated by the positive control and the test item. The corneas treated by negative control were without macroscopic damage.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The value of opacity for the negative control (0.9% NaCl) obtained during the study was 2.61 and value of permeability was 0.013. The values obtained during this study did not exceed upper limits(opacity: 2.68; permeability: 0.0448), so the study is considered acceptable.

- Acceptance criteria met for positive control: The value of IVIS for the positive control (20% imidazole in 0.9% NaCl) obtained during the study was 71.95. This value is within the acceptance limit (> 68.54 and < 90.78), so the study is considered acceptable.

Interpretation of results:

other: no prediction can be made

Conclusions:

In the Bovine Corneal Opacity and Permeability (BCOP) assay, the IVIS value for 1,3 Propene Sultone is 33.50 (> 3 and ≤ 55), therefore the classification according to UN GHS criteria for eye irritation or serious eye damage is: no prediction can be made.

Executive summary:

In the in vitro eye irritation Bovine Corneal Opacity and Permeability (BCOP) assay (152-19-5), isolated bovine corneas were exposed to 1,3-Propene sultone (99.92%) in solid form for 4 hours using the open-chamber method. 0.9% sodium chloride was used for the negative control and 20% imidazole in 0.9% sodium chloride was used for the positive control. The corneas were rinsed and then the opacity and permeability of each cornea was recorded.

The positive control gave the appropriate response (IVIS = 71.95). All 3 corneas treated with 1,3-Propene Sultone showed opacity of the tissue. The mean opacity value for the test substance was 33.50. The mean permeability OD490 for the test substance was -0.005. The IVIS for the test substance was 33.50. The IVIS for 1,3-Propenesultone is > 3 and simultaneously ≤ 55, therefore the classification according to UN GHS criteria for eye irritation or serious eye damage is: no prediction can be made.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation/corrosion

There is one in vitro skin corrosion study and one in vitro skin irritation study available.

In an in vitro skin corrosion in the human epidermal model EpiDerm (OECD 431/GLP), reconstructed human epidermis tissue was exposed to 25 mg of 1,3-Propenesultone (99.92%) for 3 and 60 minutes. H2O was used for the negative control and 8N KOH was used for the positive control. After removal of the test substance, the tissues were incubated with MTT for three hours and then extracted with isopropyl alcohol overnight at room temperature with shaking. The OD570 of isopropyl alcohol extracts was measured on a spectrophotometer. Relative cell viability was calculated for each tissue as % of the mean viability of the negative control tissues. The controls confirmed the validity of the study. The mean absolute OD570 of the three negative control tissues was ≥ 0.8 and ≤ 2.8 [1.776 (3 min) and 1.712 (60 min)]. The mean relative tissue viability (% negative control) of the positive control was < 15% [6.8% (60 min)]. Coefficient of variation (CV) was higher than 0.3 in one case but this was an acceptable deviation. The colour of the test substance did not interfere with the endpoint. The test substance is not directly MTT reducing. The average viability of tissues treated by the test item, 1,3-Propenesultone were higher than the threshold values (50 % and 15% respectively): 106.6 % ≥ 50% after 3 minutes exposure and 92.5% ≥ 15% after 60 minutes exposure. The test item should be regarded as non-corrosive.

In an in vitro skin irritation assay in a human epidermal model EpiDerm (OECD 439/GLP), reconstructed human epidermis tissue was exposed to 25 mg of 1,3-Propenesultone (99.92%) for 60±1 minutes ( 25 minutes at room temperature and the remaining 35 minutes at culture conditions). DPBS was used for the negative control and 5% SDS was used for the positive control. After removal of the test substance, tissues were post-incubated for 42±2 hours. After three hours incubation with MTT, samples were extracted with isopropyl alcohol for approximately two hours. The OD570 of isopropyl alcohol extracts was measured on a spectrophotometer. Relative cell viability was calculated for each tissue as % of the mean viability of the negative control tissues. The controls confirmed the validity of the study. The mean absolute OD570 of the three negative control tissues was ≥ 0.8 and ≤ 2.8 (1.776). The mean relative tissue viability (% negative control) of the positive control was ≤ 20% (2.8%). Standard deviation of viability of replicate tissues of all dose groups was < 18% (0.1 % for the positive control, 4.0 % for negative control and 2.7 % for the test item). The colour of the test substance did not interfere with the endpoint. The test substance is not directly MTT reducing. The average viability of tissues treated by the test item, 1,3-Propenesultone, was 56±2.734 % of the negative control average value i.e. viability was > 50 %. According to these results, the test substance is non-irritating to skin.

Serious eye damage/eye irritation:

There is one in vitro eye irritation test available.

In the in vitro eye irritation Bovine Corneal Opacity and Permeability (BCOP) assay (OECD 437/GLP), isolated bovine corneas were exposed to 1,3-Propenesultone (99.92%) in solid form for 4 hours using the open-chamber method. 0.9% sodium chloride was used for the negative control and 20% imidazole in 0.9% sodium chloride was used for the positive control. The corneas were rinsed and then the opacity and permeability of each cornea was recorded. The positive control gave the appropriate response (IVIS = 71.95). All 3 corneas treated with 1,3-Propene Sultone showed opacity of the tissue. The mean opacity value for the test substance was 33.50. The mean permeability OD490 for the test substance was -0.005. The IVIS for the test substance was 33.50. The IVIS for 1,3-Propene Sultone is > 3 and simultaneously ≤ 55, therefore the classification according to UN GHS criteria for eye irritation or serious eye damage is: no prediction can be made.

An OECD 492 GLP test was considered but the result from that test can only be “Not classified” and the opacity noted with the test substance in all 3 corneas in the OECD 437 test did not indicate that “Not classified” would be the expected conclusion.

According to the ECHA ‘Guidance on Information Requirements and Chemical Safety Assessment, Chapter R.7a: Endpoint specific guidance, Version 6.0, July 2017’:

“c. For Annex VII information requirement, as no in vivo testing is foreseen, a Weight-of-Evidence approach may be needed in order to conclude on the eye hazard potential of the substance. The assessment should take all relevant pieces of information into account. This means that in case where the available in vitro test(s) for serious eye damage/eye irritation does (do) not enable a definitive conclusion on the classification for the eye hazard to be drawn, information obtained e.g. from skin irritation testing should be considered. Thus, in case inconsistent in vitro results for serious eye damage/eye irritation are obtained, the Weight-of-Evidence including information on skin irritation may support the classification for eye irritation (Category 2), as a precautionary principle.”

- 1,3 Propenesultone was not corrosive in the OECD 431/GLP test (1,3-Propenesultone were higher than the threshold values (50 % and 15% respectively): 106.6 % ≥ 50% after 3 minutes exposure and 92.5% ≥ 15% after 60 minutes exposure.)

- 1,3-Propenesultone was not irritating in the OECD 439/GLP test though the result was close to the 50% viability threshold (1,3-Propenesultone was 56±2.734% of the negative control average value)

- The OECD 437/GLP test indicates possible irritation; all 3 corneas treated with 1,3-Propenesultone showed opacity of the tissue (mean opacity value = 33.50 compared to 44.28 for the positive control, 20% Imidazole in 0.9% NaCl).

- The close structural analogue, 1,3-Propanesultone (CAS No. 1120-71-4) is classified by the LR in the ECHA Classification and Labelling Database as Eye Damage 1 (H318).

- No in vivo testing is permitted at the Annex VII tonnage level.

Based on the weight of evidence, this supports the classification for eye irritation (Category 2), as a precautionary principle.

Justification for classification or non-classification

Based on the available information in the dossier, the substance 1,3-Propenesultone (CAS No. 21806 -61 -1) is not classified for skin irritation/corrosion and is classified as Category 2 for serious eye damage/eye irritation when considering the criteria outlined in Annex I of 1272/2008/EC.