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Administrative data

Description of key information

The key acute oral study was conducted according to OECD 423 (Acute Toxic Class method), giving an LD50 for male and female rats in the range 200 - 2000 mg/kg bw when dosed in dehydrated olive oil (NOTOX, 2003). Clinical signs observed included hunched posture, flat gait, piloerection, lethargy and alopecia (females) at both dose levels. At the higher dose level, additional clinical signs were uncoordinated movements, laboured breathing, rales, piloerection, bleeding from the snout, salivation, watery discharge from the eyes, pale appearance, ptosis and clonic spasms. Dark red forestomachs were observed in animals that died at the higher dose level, but there were no necropsy findings in animals that survived to the end of the study. 
The key acute inhalation study was conducted according to OECD 402, giving an LC50 of ca. 1611 ppm for one-hour, whole-body exposure (DCC, 1997). Longer exposure times were not used due to the corrosivity of the test substance. Clinical signs and necropsy findings for animals that died during the study reflected the corrosive nature of the test substance.
The key acute dermal study was conducted pre-GLP and also pre-dates OECD guidelines (Mellon, 1948). However the test employed suitable numbers of test animals and test concentrations. The LD50 in male rabbits was 0.68 ml/kg bw, equivalent to ca. 864 mg/kg bw (based on a measured relative density of 1.27).

Key value for chemical safety assessment

Additional information

The key oral study was selected as the only available GLP, guideline-compliant study (Reliability 1).

The key inhalation study was selected as the more recent of two GLP-compliant, guideline studies (Reliability 1). The result of the supporting study is consistent with that of the key study. Other supporting data were not suitable for determining an LC50.

The inhalation LC50 is from a one hour exposure period. When this value is adjusted (divided by 2) to account for the short exposure duration, the LC50 becomes 806 ppm, which is equivalent to approximately 5.3 mg/l.

The key dermal study was selected as the best available information (Reliability 2) from a pre-guideline, pre-GLP study. A secondary reference supports the reported LD50, although this may in fact be a citation of the same result.

Justification for classification or non-classification

On the basis of the available measured LD(C)50 values, trichloro(vinyl)silane is classified R20/21/22 'Harmful by inhalation, in contact with skin and if swallowed', according to the criteria of EU Directive 67/548/EEC and 'Acute toxic 4 (oral)', 'Acute Toxic 3 (dermal)' and 'Acute toxic 3 (vapour)' under Regulation 1272/2008.