Silicic acid, calcium salt

Endpoint summary

Description of key information

- In vitro skin irritation test using a human skin model (EpiDermTM tissue (Epi-200-Kit)): not irritating (OECD Draft Proposal for a New Guideline: In Vitro Skin Irritation: Reconstructed Human Epidermis (RhE) Test Method, Version 7.6, 9 September 2009, GLP).
- In vitro eye irritation test - Bovine Corneal Opacity and Permeability test (BCOP test): not irritating (OECD 437, September, 2009, GLP).
- In vivo eye irritation test: irritating (1272/2008/EC) (OECD405)

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

Study period:

14 Aug. 2010 - 17 Aug. 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

performed under GLP

Qualifier:

according to guideline

Guideline:

other: Commission Regulation (EC) No. 761/2009, Method B.46: “In Vitro Skin Irritation: Reconstructed human epidermis model test” adopted 23. July 2009

Deviations:

no

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, Version 7.6, 9 September 2009

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: ECVAM international validation study on in vitro tests for acute skin irritation: Report on the validity of the EPISKIN and EpiDerm assays and on the Skin Integrity Function Test (Altern Lab Anim. 2007 Dec; 35 (6): 559-601)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Protocol for IN VITRO EpiDermTM SKIN IRRITATION TEST (EPI-200-SIT), Rev. 3/23/2009, MatTek Corporation, Ashland, MA 01721, USA

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Test system:

human skin model

Remarks:

Human skin model: EpiDermTM tissue (Epi-200-Kit)

Source species:

human

Cell type:

other: human reconstructed epidermis model followed by a cell viability test

Cell source:

other: Human skin model: EpiDermTM tissue (Epi-200-Kit)

Source strain:

other: not relevant

Justification for test system used:

The test consists of a topical exposure of the neat test item to a human reconstructed epidermis model followed by a cell viability test. Cell viability is measured by dehydrogenase conversion of MTT [(3-4,5-dimethyl thiazole 2-yl) 2,5-diphenyl-tetrazoliumbromide], in cell mitochondria, into a blue formazan salt that is quantitatively measured after extraction from tissues. The percent reduction of cell viability in comparison of untreated negative controls is used to predict skin irritation potential and is used for the purpose of classification as irritating or non-irritating according to chemicals law (EU CLP, UN GHS).

Vehicle:

unchanged (no vehicle)

Details on test system:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): DPBS-Buffer
- Time after start of exposure: 60 minutes

After further incubation for about 42 hours the tissues were treated with the MTT [(3-4,5-dimethyl thiazole 2-yl) 2,5-diphenyl-tetrazoliumbromide] solution for 3 hours ± 5 min, following extraction of the colorant from the cells. The amount of extracted colorant was determined photometrically at 570 nm.

SCORING SYSTEM: The photometric absorption of the negative controls is considered as 100%. For the mean of the 3 replicates of test item and positive control, formazan production is calculated as % photometric absorption compared with the negative control. Skin irritation potential of the test item is assessed as follows: % Formazan production < 50% of negative control = Irritant; % Formazan production > 50% of negative control = Non-irritant.

Control samples:

other: Negative control: Dulbecco’s Phosphate Buffered Saline (DPBS buffer without CaCl2 and without MgCl2). Positive control: Sodium dodecylsulphate (SDS), CAS No. 151-21-3, solution in deionised H2O containing 5% SDS.

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 24.3, 24.5 and 25.5 mg of the test item were applied to each of triplicate tissues.
- Concentration (if solution): 100 %, wetted with 25 µL Dulbecco’s Phosphate Buffered Saline (DPBS)

Positive and negative controls: 30 µL were dosed per tissue

Duration of treatment / exposure:

60 minutes

Number of replicates:

Three tissues of the human skin model EpiDerm™ were treated with the test item, the negative or the positive control.

Irritation / corrosion parameter:

other: % Formazan production

Remarks:

mean % of Negative Control

Run / experiment:

Tissue 1 , 2 and 3 with test substane

Value:

119.5

Vehicle controls validity:

not applicable

Remarks on result:

other:

Remarks:

Reversibility: Not applicable.

Irritation / corrosion parameter:

other: % Formazan production

Remarks:

Mean % of Negative Control

Run / experiment:

Tissue 1, 2 and 3 with positive control

Value:

10.9

Vehicle controls validity:

not applicable

Positive controls validity:

valid

Remarks on result:

other:

Remarks:

Reversibility: Not applicable.

Irritant / corrosive response data:

The relative absorbance values were increased to 119.5% after the treatment. This value is above the threshold for irritation (50%). Therefore, the test item is considered as not irritant. Note: optical density values of more than 100% of the negative control are not unusual.

The optical density of the negative control was well within the required acceptability criterion of 1.0 < mean OD < 2.5. The positive control induced a decrease in the relative absorbance as compared to the negative control to 10.9 % (required: ≤ 20%) ensuring the validity of the test system. Variation within replicates was within the accepted range for negative control, positive control and test item. For these reasons, the result of the test is considered valid.

Interpretation of results:

GHS criteria not met

Conclusions:

After the treatment with the test item, the relative absorbance values were increased to 119.5 %. This value is well above the threshold for irritation potential (50%). Therefore, Crystalline calcium silicate hydrates (xonotlite - tobermorite) is considered as not irritant in the Human Skin Model Test.

Executive summary:

The Skin Irritation Potential of crystalline calcium silicate hydrates (xonotlite - tobermorite) was deterrmined in the Human Skin Model Test following EU-Method B.46 and OECD Guideline, Draft Proposal for a New Guideline, In Vitro Skin Irritation: Reconstructed Human Epidermis (RhE) Test Method, Version 7.6, 9 September 2009. Three tissues of the human skin model EpiDerm^TM were treated with crystalline calcium silicate hydrates (xonotlite - tobermorite) for 60 minutes. 25 mg of the solid test item (wetted with 25 µL DPBS-buffer) were applied to each tissue and spread to match the tissue size. DPBS-buffer (Dulbecco’s Phosphate Buffered Saline) was used as negative control, 5% Sodium dodecylsulphate (SDS) solution was used as positive control. The photometric absorption of the negative controls is considered as 100%. For the mean of the 3 replicates of test item and positive control, formazan production is calculated as % photometric absorption compared with the negative control. Skin irritation potential of the test item is assessed as follows: % Formazan production < 50% of negative control = Irritant; % Formazan production > 50% of negative control =Non-irritant. After treatment with the negative control, the absorbance values were within the required acceptability criterion of 1.0 < mean OD < 2.5. The positive control showed clear irritating effects. Variation within tissues was acceptable (< 18%). After the treatment with the test item, the relative absorbance values were increased to 119.5 %. This value is well above the threshold for irritation potential (50%). Therefore, crystalline calcium silicate hydrates (xonotlite - tobermorite) is considered as not irritant in the Human Skin Model Test.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 October - 11 November 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

performed under GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Elevage de Gerome (Quafier Labaste - F40260 Linke)
- Age at study initiation: 12-13 weeks
- Weight at study initiation: 2.65-3.17 kg during test
- Housing: individual wire floored stainless steel cages of dimensions 61 cm x 46 cm x 36 cm
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20°C ± 3°C
- Humidity (%): from 30% to 70%
- Air changes (per hr): at least 10 cycles per hour
- Photoperiod (hrs dark / hrs light): circadian cycle (12 hrs day/12 hrs darkness)

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 g

Duration of treatment / exposure:

At 1 hour after test item instillation, remaining test item was rinsed

Observation period (in vivo):

9 days (observations after 1, 24, 48, 72 hrs and 4, 8, and 9 days)

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): physiological rinse
- Time after start of exposure: 1 hour

SCORING SYSTEM: in accordance with OECD Guideline 405

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

other: 24, 48, and 72 hrs mean

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 72 hrs

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

other: 24, 48 and 72 hrs mean

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 9 days

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

other: 24, 48, and 72 hrs mean

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 6 days

Irritation parameter:

iris score

Basis:

animal #1

Time point:

other: 24, 48, and 72 hrs score

Score:

0.3

Max. score:

2

Reversibility:

fully reversible within: 48 hr

Irritation parameter:

iris score

Basis:

animal #2

Time point:

other: 24, 48, and 72 hrs meand

Score:

0.3

Max. score:

2

Reversibility:

fully reversible within: 48 hrs

Irritation parameter:

iris score

Basis:

animal #3

Time point:

other: 24, 48, and 72 hrs score

Score:

0.3

Max. score:

2

Reversibility:

fully reversible within: 48 hrs

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

other: 24, 48, and 72 hrs score

Score:

1.3

Max. score:

3

Reversibility:

fully reversible within: 9 days

Remarks on result:

other: redness

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

other: 24, 48, and 72 hrs score

Score:

2.3

Max. score:

3

Reversibility:

fully reversible within: 9 days

Remarks on result:

other: redness

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

other: 24, 48, and 72 hrs score

Score:

2.3

Max. score:

3

Reversibility:

fully reversible within: 6 days

Remarks on result:

other: redness

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

other: 24, 48, and 72 hrs score

Score:

1.7

Max. score:

4

Reversibility:

fully reversible within: 8 days

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

other: 24, 48, and 72 hrs score

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 6 days

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

other: 24, 48, and 72 hrs score

Score:

1.7

Max. score:

4

Reversibility:

fully reversible within: 6 days

Irritant / corrosive response data:

- conjunctivae: moderate redness noted after 1 hr, totally reversible between day 6-9, moderate to important chemosis noted after 1 hr, totally reversible between day 6-8
- iris: congestion noted after 24 hr, totally reversible on day 2
- corneal: slight corneal opacity after 1 hr, totally reversible between 3-6

Other effects:

After 1 hr, lachrymation with moistening of the eyelids and large areas aroound the eye was observed in all animals. This effect was fully reversible within 24 hours (animal 2 and 3) or 48 hrs (animal 1).

Interpretation of results:

irritating

Remarks:

Migrated information according to CLP Criteria used for interpretation of results: EU

Conclusions:

Crystalline calcium silicate hydrate (xonotlite - tobermorite) induced corneal opacity and conjunctival redness. Based on the calculated means, the test item must according to Annex I of 1272/2008/EC (CLP/EU-GHS) be classified in category 2 "irritating to eyes".

Executive summary:

An in vivo eye irritation test was performed in accordance with OECD Guideline 405 to assess the eye irritation potential of crystalline calcium silicate hydrate (xonotlite - tobermorite). The test item induced corneal opacity and conjunctival redness, but all effects were fully reversible within 9 days. Based on the calculated means, the test item must according to Annex I of 1272/2008/EC (CLP/EU-GHS) be classified in category 2 "irritating to eyes".

Reference 2

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

7 February 2011 - 17 February 2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was performed under GLP conditions and according to OECD Guideline 405. However, the study was stopped after results with the first animal and was not completed with two other animals.

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: the Elevage de Gérome (Quartier Labaste - F40260 Linxe)
- Age at study initiation: 11 weeks
- Weight at study initiation: between 2.34 kg and 2.66 kg during the test
- Housing: individual box installed in conventional air conditioned animal husbanding
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): between 17°C - 23°C
- Humidity (%): from 30% to 70%
- Air changes (per hr): 15 changes per hour
- Photoperiod (hrs dark / hrs light): circadian cycle (12 hrs day/12 hrs darkness)

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 g

Duration of treatment / exposure:

At 1 hour after test item instillation, remaining test item was rinsed

Observation period (in vivo):

10 days (observations after 1, 24, 48, 72 hrs, 4, 5, 6, 7, 8, 9, and 10 days)

Number of animals or in vitro replicates:

1

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): physiological rinse
- Time after start of exposure: 1 hour

SCORING SYSTEM: in accordance with OECD Guideline 405

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

other: 24, 48, and 72 hrs mean

Score:

0.7

Max. score:

4

Reversibility:

fully reversible within: 48 hrs

Irritation parameter:

iris score

Basis:

animal #1

Time point:

other: 24, 48, and 72 hrs score

Score:

0.3

Max. score:

2

Reversibility:

fully reversible within: 48 hrs

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

other: 24, 48, and 72 hrs score

Score:

2.3

Max. score:

3

Reversibility:

fully reversible within: 10 days

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

other: 24, 48, and 72 hrs score

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 9 days

Irritant / corrosive response data:

- conjunctivae: severe redness after 1 hr, totally reversible on day 10, severe chemosis after 1 hr, totally reversible on day 9
- iris: congestion noted after 1 hr, totally reversible on day 2
- corneal: slight corneal opacity after 1 hr, totally reversible on day 2

Other effects:

not applicable

At the request of the sponsor, the study was stopped and not completed with two other animals.

Interpretation of results:

other: irritating

Remarks:

Criteria used for interpretation of results: expert judgment

Conclusions:

Crystalline calcium silicate hydrate (xonotlite - tobermorite) induced conjunctival rednessand conjunctival oedema. No definite conclusion can be drawn as only one animal has been tested.

Executive summary:

An in vivo eye irritation test was performed in accordance with OECD Guideline 405 to assess the eye irritation potential of crystalline calcium silicate hydrate (xonotlite - tobermorite). The test item induced conjunctival redness and conjunctival oedema in one animal; all effects were fully reversible within 10 days. No definite conclusion can be drawn as only one animal has been tested.

Reference 3

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 Aug. 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

performed under GLP

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Species:

other: not relevant: in vitro test

Strain:

other: Bovine

Details on test animals or tissues and environmental conditions:

BOVINE EYES:
- Source: Freshly bovine eyes were obtained from the slaughterhouse Muller Fleisch GmbH, Enzstr. 2.4, 75217 Birkenfeld, Germany, on the day of the test

Vehicle:

physiological saline

Controls:

yes, concurrent vehicle

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 750 uL (86.5, 87.0 and 76.8 mg; average: 83.4 mg neat)

VEHICLE
- Concentration (if solution): 0.9% NaCl

NEGATIVE CONTROL
- Amount(s) applied (volume or weight with unit): 750 uL of physiological saline per cornea
- Concentration (if solution): 0.9% NaCl in deionised water

POSITIVE CONTROL
- Amount(s) applied (volume or weight with unit): 750 uL per cornea
- Concentration (if solution): imidazole solution, 20%

Duration of treatment / exposure:

4 hours +/- 5 min.

Observation period (in vivo):

Not applicable

Number of animals or in vitro replicates:

9 freshly isolated bovine cornea: negative control, positive control and test item: 3 cornea each.

Details on study design:

TEST SITE: Isolated bovine cornea

EXPOSURE OF THE CORNEA: in cornea holder, open chamber method

REMOVAL OF TEST SUBSTANCE
- Washing (if done): The test item or control items, resp., were rinsed off from the application side by changing cMEM (complete Minimum Essential Medium)

SCORING SYSTEM: The mean opacity and mean permeability values (OD490) were used for each treatment group to calculate an in vitro score:
in vitro irritancy score (IVIS) = mean opacity value + (15 x mean OD490 value).

TOOL USED TO ASSESS SCORE: Spectrophotometer and microplate reader

DATA EVALUATION: A test substance that induces an In vitro irritancy score (IVIS) ≥ 55.1 is defined as a corrosive or severe irritant.

Irritation parameter:

cornea opacity score

Remarks:

Mean in vitro Score Negative control

Basis:

other: Cornea 1, 2, and 3

Score:

0.845

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

cornea opacity score

Remarks:

Mean in vitro Score Positive control

Basis:

other: Cornea 1, 2, and 3

Score:

62.467

Reversibility:

other: not applicable

Remarks on result:

probability of severe irritation

Irritation parameter:

cornea opacity score

Remarks:

Mean in vitro Score Test substance

Basis:

other: Cornea 1, 2, and 3

Score:

0

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

The test item, crystalline calcium silicate hydrates (xonotlite - tobermorite), showed no eye irritation (values lay below negative control).

Negative and positive controls were within historical ranges.

Interpretation of results:

GHS criteria not met

Conclusions:

The test item crystalline calcium silicate hydrates (xonotlite - tobermorite) did not induce ocular irritation for both endpoints, opacity and permeability, resulting in a mean in vitro irritancy score (IVIS) of -0.583 = 0.00. It is concluded that this test is valid and that crystalline calcium silicate hydrates (xonotlite - tobermorite) is classified as non eye irritant in the Bovine Corneal Opacity and Permeability (BCOP) test under the experimental conditions described in the report.

Executive summary:

This in vitro study was performed according to OECD Guideline 437, 2009 to assess the corneal irritation and damage potential of crystalline calcium silicate hydrates (xonotlite - tobermorite) by quantitative measurements of changes in opacity and permeability in a bovine cornea (Bovine Corneal Opacity and Permeability Assay (BCOP)).

The test item crystalline calcium silicate hydrates (xonotlite - tobermorite) was brought onto the cornea of a bovine eye which previously had been incubated with cMEM without Phenol red at 32 ± 1°C for 1 hour, and whose opacity had been determined. The test item was incubated on the cornea for 4 hours at 32 ± 1°C. After removal of the test item and 2 hours post-incubation, opacity and permeability values were measured. Physiological sodium chloride solution was used as negative control. The negative control showed no irritating effect on the cornea, mean IVIS (in vitro irritancy score) was 0.845. 20% Imidazole solution was used as positive control. The positive control induced a severe irritation on the cornea, mean IVIS was 62.467. Negative and positive controls were within historical ranges.

The test item was tested pure and showed no irritating effects on the cornea of the bovine eye. The calculated mean IVIS was -0.583 = 0.00. In conclusion, it can be stated that in this study and under the experimental conditions reported, the test item crystalline calcium silicate hydrates (xonotlite- tobermorite) possesses no eye irritation potential.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

The key study available for skin irritation was an in vitro skin irritation test using a human skin model ((EpiDermTM tissue (Epi-200-Kit)). The study procedures were based on the OECD Draft Proposal for a New Guideline: In Vitro Skin Irritation: Reconstructed Human Epidermis (RhE) Test Method, Version 7.6, 9 September 2009. After treatment with the test item, the relative absorbance values were increased to 119.5%. This value is well above the threshold for irritation potential (50%). Therefore, Crystalline calcium silicate hydrates (xonotlite - tobermorite) is considered as not irritant in the Human Skin Model Test.

No supporting studies were available for skin irritation. An in vivo skin irritation was waived because no irritation is expected based on the negative results in the in vitro test and the observations of only slight erythema (not sufficient for classification) in the LLNA skin sensitisation test (Vogel, 2010, summarized in IUCLID 7.4.1).

Two key studies are available for eye irritation, an in vitro and an in vivo test. In vitro, the Bovine Corneal Opacity and Permeability test (BCOP test) was used, performed according to OECD Guideline 437, 2009. The test item Crystalline calcium silicate hydrates (xonotlite - tobermorite) did not induce ocular irritation through both endpoints, opacity and permeability, resulting in a mean in vitro irritancy score (IVIS) of -0.583 = 0.00. It is concluded that this test is valid and that Crystalline calcium silicate hydrates (xonotlite - tobermorite) is classified as non eye irritant in the Bovine Corneal Opacity and Permeability (BCOP) test under the experimental conditions described in the report.

An in vivo eye irritation test was performed in accordance with OECD Guideline 405 to assess the eye irritation potential of silicic acid, calcium salt (xonotlite - tobermorite). The test item induced corneal opacity and conjunctival redness, but all effects were fully reversible within 9 days. Based on the calculated means, however, according to Annex I of 1272/2008/EC (CLP/EU-GHS) the substance should be classified in category 2 "irritating to eyes".

A supporting in vivo eye irritation test is available in which one animal was tested in accordance with OECD Guideline 405 to assess the eye irritation potential of silicic acid, calcium salt (xonotlite - tobermorite). The test item induced conjunctival redness and conjunctival oedema in one animal; all effects were fully reversible within 10 days. At request of the Sponsor, the study was stopped and not completed with two other animals. No definite conclusion can be drawn as only one animal has been tested, however, the results are supporting the classification as irritating.

The respiratory irritation was not studied for Crystalline calcium silicate hydrates (xonotlite - tobermorite).

Effects on eye irritation: irritating

Justification for classification or non-classification

The in vitro skin irritation study indicate that silicic acid, calcium salt (xonotlite - tobermorite) does not induce significant irritation to the skin, in vitro.Therefore, it can be concluded that the substance is not irritating to the skin and therefore does not need to be classified as such according to the criteria outlined in Annex I of 1272/2008/EC (CLP/EU-GHS).

Although the in vitro eye irritation test does not indicate that silicic acid, calcium salt (xonotlite - tobermorite) is irritating to the eye, the in vivo studies show effects on corneal opacity and conjunctival redness. Based on the results of the in vivo studies, silicic acid, calcium salt (xonotlite - tobermorite) however, according to Annex I of 1272/2008/EC (CLP/EU-GHS) the substance needs to be classified in category 2 "irritating to eyes".