destillation fraction of chlorosilanes

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Effect on fertility: via oral route

Dose descriptor:

NOAEL

500 mg/kg bw/day

Effect on fertility: via inhalation route

Dose descriptor:

NOAEC

2 666 mg/m³

Additional information

MS-Silane is a UVCB comprised of 13 constituents. They are a structurally similar group of silanes with varying levels of carbon, oxygen and chlorine substitution.

Reliable data are available for the hydrolysis products of three of the constituents of MS-Silane. In all of the tests conducted, no adverse effects were observed at the highest dose tested (see Table 1).

Table 1. Available Reproductive Toxicity Studies for Three MS-Silane Constituents

Constituent	% in MS-Silane	Reproductive Toxicity (OECD 422)
75-78-5 dichloro(dimethyl)silane	20-35%	>/= 500 mg/kg bw/day (oral, highest dose tested)
75-77-4 chlorotrimethylsilane	0-5%	>/= 600 ppm (inhalation, highest dose tested)
10026-04-7 tetrachlorosilane	0-15%	>/= 100 mg/kg bw/day (oral, highest dose tested)

Based on the available data and the structural similarity of the other constituents of MS-Silane, MS-Silane is not expected to be a reproductive toxicant.

Data Waiver for 2 -Generation Reproductive Toxicity Test

In accordance with section 3 of REACH Annex XI, the study does not need to be conducted as the substance is manufactured and used under SCC. This substance is handled under Strictly Controlled Conditions in accordance with REACH regulation Annex XI. Site documentation to support safe handling arrangements including the selection of engineering, administrative and personal protective equipment controls in accordance with risk-based management systems is available at each Manufacturing site.

This substance is handled under Strictly Controlled Conditions in accordance with REACH regulation Article 18(4). Site documentation to support safe handling arrangements including the selection of engineering, administrative and personal protective equipment controls in accordance with risk-based management systems is available at each Manufacturing site.

Short description of key information:
There are no data regarding the potential for MS-Silane or its constituents to have adverse effects on fertility, therefore data for the hydrolysis product of three structurally similar constituents of MS-Silane [dichloro(dimethyl)silane, CAS 75-78-5 (20 -35% in MS-Silane); chlorotrimethylsilane, CAS 75-77-4 (0 - 5% in MS-Silane); and tetrachlorosilane, CAS 10026-04-7 (0 - 15% in MS-Silane)] have been used to read-across. As has been demonstrated by the acute toxicity and irritation/corrosion data, there would also be corrosive local effects from HCl if dichloro(dimethyl)silane, chlorotrimethylsilane or tetrachlorosilane were to be administered. All three hydrolysis products have reliable OECD 422 studies available.

For two of the three hydrolysis products (Dimethylsilanediol and tetraethyl orthosilicate) Sprague-Dawley rats were treated by oral gavage. No adverse effects on reproduction were observed in either study at the highest dose tested (500 mg/kg bw/day and 100 mg/kg bw/day, respectively). The results from the study on tetrachlorosilane (TEOS), however, were not felt to be as representative of MS-Silane as a whole due to the hydrolysis products of TEOS being ethanol and silicic acid. Thus the NOAEL for dimethylsilanediol was used in the CSR.

For the remaining hydrolysis product, trimethylsilanol, Sprague-Dawley rats were treated by vapour inhalation. No adverse effects on reproduction were observed at the highest dose tested (600 ppm, equivalent to 2666 mg/m3).

There are no reproductive toxicity data for the dermal route.

Effects on developmental toxicity

Description of key information

There are no data regarding the potential for MS-Silane or its constituents to have adverse effects on fetal development, therefore data for the hydrolysis product of three structurally similar constituents of MS-Silane [dichloro(dimethyl)silane, CAS 75-78-5 (20 -35% in MS-Silane);  chlorotrimethylsilane, CAS 75-77-4 (0 - 5% in MS-Silane); and tetrachlorosilane, CAS 10026-04-7 (0 - 15% in MS-Silane)] have been used to read-across.  As has been demonstrated by the acute toxicity and irritation/corrosion data, there would also be corrosive local effects from HCl if dichloro(dimethyl)silane, chlorotrimethylsilane or tetrachlorosilane were to be administered. All three hydrolysis products have reliable OECD 422 studies available.  
For two of the three hydrolysis products (dimethylsilanediol and tetraethyl orthosilicate) Sprague-Dawley rats were treated by oral gavage. No adverse effects on fetal development were observed in either study at the highest dose tested (500 mg/kg bw/day and 100 mg/kg bw/day, respectively).  As discussed above, the results for dimethylsilanediol are considered to be most representative of MS-Silane as a whole.
For the remaining hydrolysis product, trimethylsilanol, Sprague-Dawley rats were treated by vapour inhalation.  No adverse effects on fetal development were observed at the highest dose tested (600 ppm, equivalent to 2666 mg/m3).  
There are no developmental toxicity data for the dermal route.

Effect on developmental toxicity: via oral route

Dose descriptor:

NOAEL

500 mg/kg bw/day

Effect on developmental toxicity: via inhalation route

Dose descriptor:

NOAEC

2 666 mg/m³

Additional information

MS-Silane is a UVCB comprised of 13 constituents. They are a structurally similar group of silanes with varying levels of carbon, oxygen and chlorine substitution.

Reliable data are available for the hydrolysis products of three of the constituents of MS-Silane. In all of the tests conducted, no adverse effects were observed at the highest dose tested (see Table 2).

Table 2. Available Developmental Toxicity Studies for Three MS-Silane Constituents

Constituent	% in MS-Silane	Developmental Toxicity (OECD 422)
75-78-5 dichloro(dimethyl)silane	20-35%	>/= 500 mg/kg bw/day (oral, highest dose tested)
75-77-4 chlorotrimethylsilane	0-5%	>/= 600 ppm (inhalation, highest dose tested)
10026-04-7 tetrachlorosilane	0-15%	>/= 100 mg/kg bw/day (oral, highest dose tested)

Based on the available data and the structural similarity of the other constituents of MS-Silane, MS-Silane is not expected to be a developmental toxicant.

Data Waiver forPrenatal Developmental toxicity Study

In accordance with section 3 of REACH Annex XI, the study does not need to be conducted as the substance is manufactured and used under SCC. This substance is handled under Strictly Controlled Conditions in accordance with REACH regulation Annex XI. Site documentation to support safe handling arrangements including the selection of engineering, administrative and personal protective equipment controls in accordance with risk-based management systems is available at each Manufacturing site.

This substance is handled under Strictly Controlled Conditions in accordance with REACH regulation Article 18(4). Site documentation to support safe handling arrangements including the selection of engineering, administrative and personal protective equipment controls in accordance with risk-based management systems is available at each Manufacturing site.

Justification for classification or non-classification

The available read-across study on the hydrolysis products of MS-Silane did not reveal any effects on fertility or development of rats, therefore suggesting that there is no justification to classify MS-Silane for reproductive and developmental toxicity. The other hydrolysis product, hydrogen chloride, has no known reproductive or developmental toxicity effects.