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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Description of key information

Oral:
WoE approach: not acutely toxic based on repeated dose toxicity studies (DRF and OECD TG 422), RA CAS 78-62-6: LD50=9775 mg/kg bw

Inhalation:
OECD TG 403: LC50 >4700 mg/m³

Dermal:

There are no data available for acute toxicity via the dermal route (data waiving according to Column 2 of REACH Annex VIII, Section 8.5.3).

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Referenceopen allclose all

Endpoint:
acute toxicity: oral
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Endpoint:
acute toxicity: oral
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
Please refer to the attached justification below and the overall justification for grouping of substances attached in IUCLID Section 13.
Reason / purpose for cross-reference:
read-across source
Key result
Sex:
male
Dose descriptor:
LD50
Effect level:
11.3 mL/kg bw
Based on:
test mat.
95% CL:
8.22 - 15.6
Remarks on result:
other:
Remarks:
equivalent to LD50 = 9775 mg/kg bw (Chemical Hygiene Fellowship, 1979, CAS 78-62-6)
Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulations (EC) No 1272/2008
Conclusions:
One study is available from structural analogue substance CAS 78-62-6. The LD50 for CAS 78-62-6 was estimated to be 9775 mg/kg bw. As explained in the analogue justification, the differences between the target and the source are unlikely to lead to differences in the oral LD50.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
The hazard assessment is based on a weight of evidence approach taking into account repeated dose toxicity studies. The database is, therefore, sufficient to fulfil the standard information requirements set out in Annex VII, Item 8.5, in accordance with Annex XI, Item 1.2, of Regulation (EC) No. 1907/2006.

Acute toxicity: via inhalation route

Link to relevant study records
Reference
Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
30-08-1988 to 12-09-1988
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to the appropriate OECD test guideline, and in compliance with GLP.
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
yes
Remarks:
Report lacking data on whether clinical examination and physical measurements were conducted.
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes
Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Not reported.
- Weight at study initiation: 175-200 g ( Males and Females).
- Housing: The rats were housed in stainless steel, wire mesh bottomed cages of conventional design. At the onset of experiment, the animals were moved into special stainless steel cages. These cages were designed to house the animals during the exposure periods. The animals were returned to their original housing after the exposure period.
- Diet : The animals were fed PURINA Rodent Chow ad libitum except during the exposure period.
- Water : The animals were fed water ad libitum except during the exposure period.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 30 -50
- Air changes (per hr): 14 - 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: Not reported
Route of administration:
inhalation: vapour
Type of inhalation exposure:
whole body
Vehicle:
air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Exposure was conducted in stainless steel and glass exposure chambers. The chambers were operated under dynamic conditions.
- Exposure chamber volume: 450-litre
- Method of holding animals in test chamber: Not reported.
- Source and rate of air: Airflow rates through the chambers were monitored continuously by calibrated Magnehelic gauges connected across orifices at the chamber inlets.
- Method of conditioning air: Not reported
- System of generating particulates/aerosols: Test material was introduced into the test chamber through a specially designed glass J-tube with a flow FMI Lab pump. Laboratory air filtered with a Matheson 462 cartridge filter passed through the J-tube. The air/vapour mixture entered the top of the chamber where it was diluted with room air. Heating tape was used to heat the air which passed through the J-tube, and glass beads were used to further help vaporize the test material. After the exposure period, the vapour generating equipment was turned off and the vapour concentration in the chamber was allowed to return to zero.
- Method of particle size determination: Not reported.
- Treatment of exhaust air: The exhaust air was filtered (hepa and carbon), cleaned with a water cyclone, then exhausted from the roof of the building.
- Temperature, humidity, pressure in air chamber: Chamber temperature and relative humidity were monitored with Cole-Parmer Model No.3310-40 (certified) temperature and humidity gauges.

TEST ATMOSPHERE
- Brief description of analytical method used: Not reported


Analytical verification of test atmosphere concentrations:
not specified
Duration of exposure:
4 h
Concentrations:
The test material target concentration was 5.0 mg/l. The actual nominal chamber concentration was 4.7 mg/l (calculation by weight).
No. of animals per sex per dose:
5 males and 5 females.
Control animals:
yes
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Gauge readings were recorded hourly during the chamber period. Animals were observed once a day during weekdays. Individual animal body weights were taken prior to exposure and on days 7 and 14 after exposure.
- Necropsy of survivors performed: Not reported
- Other examinations performed: body weight
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 4 700 mg/m³ air
Based on:
test mat.
Exp. duration:
4 h
Mortality:
No mortalities were observed in either groups during the exposure or post-exposure periods.
Clinical signs:
other: Not reported.
Body weight:
No apparent test material related effect on body weights.
Gross pathology:
Not reported.

 Table 2. Mortality Data.

Test Material Concentration (mg/l)

Number of Dead/Number exposed

Males

Females

0

0/5

0/5

4.7

0/5

0/5

 

Table 3. Mean Body Weight Data (g).

Days After Exposure

Group I, Control

Test Group II

Males

Females

Males

Females

0

189 ± 5

183 ± 10

188 ± 5

183 ± 12

7

242 ± 8

214 ± 15

248 ± 9

205 ± 15

14

295 ± 13

233 ± 21

305 ± 15

230 ± 20

Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulation (EC) No 1272/2008
Conclusions:
In an acute inhalation (vapour) study conducted in compliance with OECD 403 and GLP, in which rats were exposed to to >4700 mg/m³ dimethoxydimethylsilane for four hours resulted in no mortality. Therefore, LC50 was determined to be >4700 mg/m³.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LC50
Value:
> 4 700 mg/m³ air
Quality of whole database:
The available information comprises an adequate and reliable study, and is thus sufficient to fulfil the standard information requirements set out in Annex VIII, 8.5, of Regulation (EC) No 1907/2006.

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

No studies were identified to assess the acute oral toxicity potential of dimethoxy(dimethyl)silane (CAS 1112-39-6). Based on a weight-of-evidence based adaptation according to REACH Annex XI, section 1.2 considering the results of a 7-day dose-range finding study (Dow Corning Corporation, 2008) and a combined repeated dose and reproduction / developmental screening study (Dow Corning Corporation, 2010), dimethoxy(dimethyl)silane is not expected to be acutely toxic. In addition, reliable data on acute oral toxicity for the structural analogue substance diethoxy(dimethyl)silane (CAS 78-62-6, LD50 = 9775 mg/kg bw) strengthen the conclusion, that dimethoxy(dimethyl)silane does not warrant classicification for acute oral toxicity according to Regulation (EC) No. 1272/2008.

 

The key acute inhalation study was the only study available. The study was conducted in compliance with GLP and according to OECD TG 403. Exposure of rats to dimethoxy(dimethyl)silane (CAS 1112-39-6) vapour at a concentration of 4.7 mg/L (4700 mg/m³) for four hours resulted in no mortality. Therefore LC50 was determined to be >4700 mg/m³ (Dow Corning Corporation, 1989).

 

No studies were available to assess the acute dermal toxicity potential of dimethoxy(dimethyl)silane (CAS 1112-39-6). However, in accordance with Column 2 of REACH Annex VIII, the acute toxicity study via the dermal route (required in Section 8.5.3) does not need to be conducted as reliable data via the oral and inhalation routes are available. 


Justification for classification or non-classification

The available data on acute toxicity by the oral and inhalation route do not meet the criteria for classification according to Regulation (EC) 1272/2008, and are therefore conclusive but not sufficient for classification of the registered substance.