Silicon tetrachloride

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25.09.1995 to 27.03.1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1998

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

1-hour exposure

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Silicon tetrachloride

EC Number:

233-054-0

EC Name:

Silicon tetrachloride

Cas Number:

10026-04-7

Molecular formula:

Cl4Si

IUPAC Name:

tetrachlorosilane

Test material form:

liquid

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories
- Age at study initiation: 6-7 weeks
- Weight at study initiation: 182 +/- 25 grams (males) and 136 +/- 12 grams (females)
- Fasting period before study: No data
- Housing: Stainless steel, wire mesh bottomed cages
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: One week


ENVIRONMENTAL CONDITIONS
- Temperature (°F): 65-78
- Humidity (%): 40-70
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: 12.10.1995 To: 27.10.1995

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

Exposure duration: One hour plus six minutes (T99) using whole body exposure methods

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Plexiglass whole body chamber
- Exposure chamber volume: 175 L
- Method of holding animals in test chamber: None
- Source and rate of air: 42-45 air changes per hour (from room air)
- Method of conditioning air: Filtered (HEPA and activated carbon)
- Treatment of exhaust air: No data
- Temperature, humidity, pressure in air chamber: 22 ± 2°C, 30-50%, under slight negative pressure.


TEST ATMOSPHERE
- Brief description of analytical method used: Gas chromatograph and mass spectrometer
- Samples taken from breathing zone: No data, but four samples were collected for each exposure period.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

1 h

Concentrations:

1209, 1497 and 3051 ppm (nominal) and 202, 307 and 777 ppm (actual mean)

No. of animals per sex per dose:

5/sex/dose

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations for clinical signs of toxicity: daily. Body weights: Prior to exposure and on Days 1, 8 and 15.
- Necropsy of survivors performed: yes
- Other examinations performed: Gross pathology.

Statistics:

The inhalation median lethal nominal concentration (LC50), 95% fiducial limits, approximate slope of the dose-response curve were calculated using SAS/STAT Probit program. Mean body weights and standard deviations were also calculated.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

1 312 ppm

95% CL:

> 1 006 - < 1 529

Exp. duration:

1 h

Remarks on result:

other: equivalent to 9117 mg/m3 based on MW of 169.9 g/mol.

Mortality:

All animals died at the highest concentration. Three animals died (1 male and 2 females) at the nominal concentration of 1209 ppm and 8 died (5 males and 3 females) at the concentration of 1497 ppm.

Clinical signs:

other: In the following summation, the study day or range of study days of onset is presented parenthetically after each clinical sign, with the day of exposure being study day 1. Clinical signs noted in a majority of the 1209 ppm rats included difficulty breath

Body weight:

Body weights were initially reduced at one week post-exposure, but surviving animals were gaining weight by the end of the observation period.

Gross pathology:

Among the 10 rats that survived to the scheduled necropsy, missing, misshapen and/or shrunken extremities were noted for nine, as was discoloration of the extremities. Uni- or bilateral corneal opacity was seen in six rats that survived to the scheduled necropsy. Obstructed nostrils were present for the two 1497 ppm rats that survived and various external staining was seen in two 1209 ppm rats that survived. A total of 21 rats died on the study. Findings seen at necropsy in approximately one-half or more of these rats included various external staining (N = 20), discoloration of the extremities (N = 17), liver congestion (N = 17), pulmonary haemorrhage, congestion and/or consolidation (N = 16), unilateral or bilateral corneal opacity (N = 15), obstructed nostrils (N = 15), pulmonary ectasia (N = 11), decreased or absent body fat (N = 11), blood in the gastrointestinal lumen (N = 10) and dehydration. In addition, missing, misshapen and/or shrunken extremities and gaseous distension of the gastrointestinal tract were each seen in six rats that died.

Other findings:

Potential target organs: None specifically identified in the report, however, clinical signs and necropsy findings were consistent with the respiratory tract and eyes being target organs. Responses were generally consistent between males and females.

Any other information on results incl. tables

Number of deaths at each dose level:

Sex	Dose level (ppm)	No. Deaths	Days to Death
Males	1209	1	14
	1497	5	6, 7, 7 ,8 ,8
	3051	5	1, 1, 1, 1, 2
Females	1209	2	9, 11
	1497	3	7, 11, 12
	3051	5	2, 2, 2, 3, 3

Applicant's summary and conclusion

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

In the acute inhalation toxicity study, conducted according to a protocol similar to OECD Test Guideline 403 and in compliance with GLP, an LC50 value of 1312 ppm (equivalent to 9117 mg/m3 based on MW of 169.9 g/mol) was concluded.