Registration Dossier

Administrative data

Description of key information

In the key acute oral toxicity study (Mellon Institute, 1956), the LD50 in male Wistar rats was 5600 mg/kg. At the upper dose level of 7950 mg/kg, clinical signs included violent convulsions prior to death, and haemorrhagic lungs, mottled livers and kidneys and slightly congested adrenals were seen at necropsy. There were no deaths, clinical signs or necropsoy findings at the lower dose level of 3980 mg/kg. 
In the key acute dermal toxicity study (Mellon Institute, 1956), the LD50 in male New Zealand White rabbits was 5753 mg/kg. At the high dose (9669 mg/kg), slightly congested lungs, pale and pitted kidneys and mottled livers were seen at necropsy. No clinical signs were reported, although there were signs of local irritation and necrosis.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
5 600 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
5 753 mg/kg bw

Additional information

Only limited data are available on the acute toxicity of 3-(triethoxysilyl)propiononitrile. These relate to a study (Mellon, 1956) which pre-dates GLP, but was otherwise scientifically acceptable and, for oral and dermal exposures, was similar to the appropriate OECD guidelines (OECD 401 and 403 respectively). For the oral and dermal routes, the study has therefore been assigned reliability 2 and allocated as key studies. The LD50 values in both studies were well in excess of the upper limit for acute toxicity testing according to current EU guidelines (2000 mg/kg).

The inhalation exposure did not meet current guideline requirements, but adds weight of evidence to the low acute toxicity of the substance. It has therefore been assigned reliability 4 and used as supporting information only.

Justification for classification or non-classification

Based on the available measured LD(C)50 values, 3-(triethoxysilyl)propiononitrile does not meet the criteria for classification for acute toxicity according to EU Directive 67/548/EEC or Regulation 1272/2008.