Silicon tetrachloride

Endpoint summary

Description of key information

In the key in vivo skin irritation study, conducted using a protocol similar to OECD Test Guideline 404 but pre-GLP, silicon tetrachloride was concluded to be corrosive to skin (Stauffer Chemical Company, 1973).

There are no high-reliability studies available for eye irritation or respiratory irritation.

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

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

Assessment of the scoring did not include 72 hours exposure

GLP compliance:

no

Species:

rabbit

Strain:

not specified

Type of coverage:

occlusive

Preparation of test site:

other: intact and abraded

Vehicle:

unchanged (no vehicle)

Controls:

not required

Duration of treatment / exposure:

Four hours

Observation period:

48 hours

Number of animals:

6

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 4, 24 and 48 hours

Score:

ca. 4.22

Max. score:

8

Reversibility:

no data

Remarks on result:

other: Intact and abraded skin. See Executive summary for calculation.

Irritation parameter:

erythema score

Remarks:

Intact skin

Basis:

animal #1

Time point:

24/48 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Irritation parameter:

erythema score

Remarks:

Intact skin

Basis:

animal #2

Time point:

24/48 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Irritation parameter:

erythema score

Remarks:

Intact skin

Basis:

animal #3

Time point:

24/48 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Irritation parameter:

erythema score

Remarks:

Intact skin

Basis:

animal #4

Time point:

24/48 h

Score:

1.5

Max. score:

4

Reversibility:

not reversible

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Remarks:

Intact skin

Basis:

animal #5

Time point:

24/48 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Irritation parameter:

erythema score

Remarks:

Intact skin

Basis:

animal #6

Time point:

24/48 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Remarks:

Intact skin

Basis:

animal #1

Time point:

24/48 h

Score:

3.5

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Irritation parameter:

edema score

Remarks:

Intact skin

Basis:

animal #2

Time point:

24/48 h

Score:

2

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Irritation parameter:

edema score

Remarks:

Intact skin

Basis:

animal #3

Time point:

24/48 h

Score:

4

Max. score:

4

Remarks on result:

positive indication of irritation

Irritation parameter:

edema score

Remarks:

Intact skin

Basis:

animal #4

Time point:

24/48 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Remarks:

Intact skin

Basis:

animal #5

Time point:

24/48 h

Score:

3.5

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Irritation parameter:

edema score

Remarks:

Intact skin

Basis:

animal #6

Time point:

24/48 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Remarks on result:

other: scores at 24/48/72 hours were not given.

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Remarks on result:

other: scores at 24/48/72 hours were not given.

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Remarks on result:

other: scores at 24/48/72 hours were not given.

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Remarks on result:

other: scores at 24/48/72 hours were not given.

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Remarks on result:

other: scores at 24/48/72 hours were not given.

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Remarks on result:

other: scores at 24/48/72 hours were not given.

Other effects:

In five of six animals tested, there was evidence of corrosivity (grade 3 (one animal) or 4 (four animals) erythema) at 48 hours post-treatment. No skin reaction was observed in the sixth animal, but this is unexpected, and considered as unreliable result.

Interpretation of results:

Category 1A (corrosive) based on GHS criteria

Conclusions:

In the in vivo skin irritation study, conducted using a protocol similar to OECD Test Guideline 404 but pre-GLP, silicon tetrachloride was concluded to be corrosive to skin.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

In the key in vivo skin irritation study for silicon tetrachloride, conducted using a protocol similar to OECD Test Guideline 404 but pre-GLP, 0.5 ml undiluted silicon tetrachloride were applied onto intact and abraded skin of six albino rabbits, under an occlusive dressing for 4 hours. The skin was washed after 4 hours. Skin reactions were then graded at 4, 24 and 48 hours post-exposure. The test material was considered corrosive when tissue destruction was observed on any of the six intact skin sites with or without similar destruction on the abraded areas. The primary irritation index was calculated by adding the values for erythema/eschar formation and oedema at 4, 24 and 48 hours for intact and abraded skin, and dividing by six to obtain and individual score for each rabbit. The combined average of the six individual scores was the primary irritation index. The primary irritation index for silicon tetrachloride was 4.22. The test substance was concluded to be corrosive to skin (Stauffer Chemical Company, 1973).

In another in vivo skin irritation toxicity study, conducted according to OECD Test Guidelines for Testing of Chemicals ISBN-92-64-1221-4 (1981) but not in compliance with GLP, animals were exposed under occlusive and semi-occlusive conditions to silicon tetrachloride for three minutes only. It was concluded that silicon tetrachloride was irritating to the skin of rabbits (Asta-Werke Aktiengesellschatf Toxikologisches Institut, 1982).

In an in vivo skin irritation study, without details as to whether it was conducted to a test guideline or in compliance with GLP, skin injury in the form of erythema occurred in a rabbit belly vesicant test. No further details were provided (Union Carbide, undated).

 

In a very limited summary of a skin irritation study, conducted prior to the adoption of OECD Test Guidelines and GLP, silicon tetrachloride was corrosive to the skin of one rabbit. The test substance applied to the shaven abdominal skin of a single rabbit caused denaturation in about ten minutes. No further details available (Rowe et al., 1948).

In a very limited summary of a skin irritation study, conducted prior to the adoption of OECD Test Guidelines and GLP, undiluted silicon tetrachloride was irritating to the skin of rabbits (score of 4/5) (Mellon Institute, 1951).

In an in vivo skin irritation study, not conducted according to any OECD Test Guideline or in compliance with GLP, silicon tetrachloride was corrosive to rabbit skin following 24-hour exposure to undiluted test material. No further information is available (Younger Laboratories, 1978).

In a skin irritation study, conducted prior to the adoption of OECD Test Guidelines and GLP, silicon tetrachloride was corrosive to the skin of rabbits (Younger Laboratories, 1967).

No reliable studies for eye irritation are available. However, since the available data indicate that silicon tetrachloride is corrosive to skin, it is not appropriate to carry out additional testing for eye irritation. Available supporting studies confirms the corrosivity of silicon tetrachloride to the eyes.

In a very limited summary of an acute eye irritation study, conducted prior to the adoption of OECD Test Guidelines and GLP, undiluted silicon tetrachloride was corrosive to the eyes of rabbits (Mellon Institute, 1951).

In a very limited IUCLID 2000 summary of an eye irritation study (reliability score 4), conducted prior to the adoption of OECD Test Guidelines and GLP, undiluted silicon tetrachloride was corrosive to the eyes of rabbits (Rowe et al., 1948).

In a very limited summary of an in vivo eye irritation study, not conducted according to OECD Test Guideline or in compliance with GLP, silicon tetrachloride was concluded to be corrosive to the eyes of rabbits (Younger Laboratories, 1978).

In an eye irritation study, conducted prior to the adoption of OECD Test Guidelines and GLP, 0.1 ml of undiluted silicon tetrachloride was instilled into the conjunctival sac of the right eye of each of three rabbits. The eyes were rinsed with warm isotonic saline solution after 24 hours, two minutes or 30 seconds. Observations occurred over several days for inflammation. One animal exposed for 24 hours had the lids closed within one hour and oedema around the eye was observed. The cornea was opalescent and pupil size barely discernible. Copious discharge and beet-redness of the conjunctivae were recorded. Overnight, the iris was invisible and remained as that throughout the observation period. For the animal exposed for two minutes, the degree of inflammation after one hour was similar to the animal exposed for 24 hours. Following 24 hours, the eyesight had been destroyed. For the animal exposed for 30 seconds, washing had little effect. The initial score was slightly less compared to the other animals. However, the eyesight was destroyed in less than 24 hours. The maximum score was 110 out of a possible 110. Consequently, it was concluded that silicon tetrachloride is corrosive to the eyes or rabbit (Younger Laboratories, 1967).

In a very limited summary of an in vivo eye irritation study, not conducted according to OECD Test Guideline or in compliance with GLP, severe irritation occurred in the eye of rabbits (Union Carbide, undated). 

Justification for classification or non-classification

Based on the available skin irritation/corrosion data that show the test substance to be corrosive to the skin, silicon tetrachloride requires classification for skin corrosion Category 1A and severe eye damage Category 1, H314 ‘Causes severe skin burns and eye damage’ according to Regulation (EC) No. 1272/2008.

The additional hazard statement ‘EUH071 Corrosive to the respiratory tract’ (1272/2008/EC) is applied, in accordance with related chlorosilane substances and the findings of a limited acute inhalation study, and based on the expected respiratory tract damage caused by the hydrolysis product HCl.

The current entry in Annex VI of Regulation (EC) No 1272/2008 includes classification for skin and eye irritation Category 2. However, the available data indicate that this classification is not sufficient.