Trichloro(methyl)silane

Endpoint summary

Description of key information

The rat acute oral LD50 values were reported to be <0.25 ml/kg and <1 ml/kg for males and females, repectively in a key study for undiluted test material (BRRC 1981), equivalent to ca. <320 mg/kg bw in males. The key acute inhalation study (DCC 1997) reported a 1 hour LC50 value of 1365ppm (equivalent to 8.3 mg/l) and the acute dermal LD50 was 1804 mg/kg in males and 1076 mg/kg in females (BRRC 1981). The necropsy findings of the decedents identified distended and fluid filled stomachs and discoloured internal organs. All the key studies were well reported and conducted according to a test protocol that is comparable to the EU test method.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

320 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

8 345 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

1 076 mg/kg bw

Additional information

The most recent and reliable studies were selected as key. Regarding the LD/LC₅₀s for acute oral and inhalation, the results from supporting studies are consistent with the key studies in that they trigger a proposal for classification. No supporting studies are available for the dermal endpoint.

Since trichloro(methyl)silane is rapidly hydrolysed to methylsilanetriol and hydrogen chloride in the presence of moisture, adverse effects observed following acute exposure by all routes will be dominated by local corrosive effects, and other apparently adverse systemic effects could possibly be secondary to these local effects.

Justification for classification or non-classification

On the basis of the available data, the test substance is labelled 'R20/21/22 Harmful by inhalation, in contact with skin and if swallowed', under Directive 67/548/EEC. There is currently no classification for acute toxicity endpoints in Annex I of 67/548/EEC.

Based on an oral LD₅₀of less than 320 mg/kg bw it is proposed that trichloro(methyl)silane be classified as Acute Toxic 4 (oral) under Regulation 1272/2008. Similarly, for the dermal route it is proposed that trichloro(methyl)silane be classified as Acute Toxic 4 (dermal), based on the LD₅₀in females of 1076 mg/kg bw and 1804 mg/kg bw in males. An LC₅₀of 8.4 mg/l (1 -hour) leads to the proposal that trichloro(methyl)silane be classified as Acute Toxic 3 (vapour) for the inhalation route.