Registration Dossier

Administrative data

Description of key information

The key study for acute oral toxicity (BRRC 1990) was conducted according to a test protocol that is comparable to the now-deleted OECD Test Guideline 401, but not in compliance with GLP. The acute oral LD50 was identified to be 893 mg/kg bw for males and 741 mg/kg bw for females.

The key study for acute dermal toxicity (BRRC 1990) was conducted according to a test protocol that is comparable to the appropriate OECD Test Guideline 402, but not in compliance with GLP. The acute dermal LD50 was identified to be 2497 mg/kg bw for males and 2172 mg/kg bw for females.

The key acute inhalation toxicity study (BRRC 1990) was conducted according to a protocol similar to OECD Test Guideline 403, not in compliance with GLP. 3-Trimethoxysilylpropane-1-thiol did not cause any deaths in Sprague-Dawley rats following a six hour exposure to saturated vapour.  

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LD50
Value:
741 mg/kg bw
Quality of whole database:
The key study for acute oral toxicity was conducted according to a test protocol that is comparable to the appropriate OECD test guideline, but not in compliance with GLP.

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 172 mg/kg bw
Quality of whole database:
The key study for acute dermal toxicity was conducted according to a test protocol that is comparable to the appropriate OECD test guideline, but not in compliance with GLP.

Additional information

The key study for acute oral toxicity (BRRC 1990) reports LD50 values of 893 mg/kg bw for males and 741 mg/kg bw for females. The clinical signs included sluggishness, unsteady gait, lacrimation, yellow or red wetness or stains on the periurogenital fur, blood in the urine, a red crust around the nose and eyes, and prostration. The animals that died revealed discoloured and/or mottled lungs (pink, red or salmon-coloured), discoloured stomachs and intestines (white to yellow, red or grey), gas and liquid filled stomachs and intestines, dark red or mottled tan livers, dark red to brown kidneys, liquid-filled abdominal cavities, one bladder filled with red liquid and blood in urine. Survivors had mottled pink to red lungs. One male had small mottled testes with cream-coloured foci and red submandibular lymph nodes.

Supporting acute oral toxicity studies were also available, which did not meet current guideline requirements or were conducted according to a similar test protocol and support the conclusion of the key study (DCC, 1969, DCC 1963, Consultox, 1976). The selected key study was the most recent and gave the most conservative result, but all results would lead to the same classification conclusion of Acute Category 4 for oral toxicity.

An acute oral toxicity study is also available for the analogous substance from 3-(triethoxysilyl)propanethiol (CAS 14814 -09 -6) which reports an LD50value of 6.17 ml/kg (estimated to be equivalent to 6108 mg/kg bw) in rats in a reliable study conducted according to a protocol equivalent to the now-deleted OECD Test Guideline 401 (Carnegie-Mellon 1976). In the highest dose group (16 ml/kg) the animals were seen to be sluggish, deep breathing, with tremor-like muscular spasms and loss of coordination. The symptoms progressed to salivation and convulsions followed by the death of all three animals. Similar, but milder clinical signs were evident in the lower dosage groups. In victims, petechial haemorrhages or congestion was observed in the lungs. This was accompanied with mottled livers, slightly speckled and congested kidneys and distended and liquid or gas-filled intestines and stomachs. Nothing remarkable was seen in survivors.

The key study for acute dermal toxicity (BRRC 1990) reports LD50 values of 2497 mg/kg bw for males and 2172 mg/kg bw for females. The clinical signs included sluggishness, unsteady gait, spasmodic movement, diarrhoea and red discharge around nose, mouth and anus. Affected animals recovered with two to three days. Necropsy of animals that died revealed red lungs, trachea filled with blood, the stomach of one animal had a red focal area, dark red kidneys, kidneys filled with blood or a yellow to green gelatinous material, a dark red bladder, blood in the urine of one animal and dark red enlarged lymph nodes. There were also instances of vascularisation and haemorrhages on the skin. Gross pathological examination of survivors revealed mottled red lungs, tracheas filled with blood and excoriation of the treated skin.

Additional acute dermal toxicity studies were also available for the registration substance, which did not meet current guidelines, but these add supporting information for this endpoint and support the conclusion of the key study (DCC 1969, DCC 1963).

An acute dermal toxicity study is also available for the analogue substance 3-(triethoxysilyl)propanethiol (CAS 14814 -09 -6) which reports and LD50 value of 2.52 ml/kg (estimated to be equivalent to 2494 mg/kg bw) in rat in a reliable study conducted according to a protocol equivalent to OECD Test Guideline 402 (Carnegie-Mellon 1976). Erythema, ecchymosis, scabs and desquamation were evident at application site with no other reported clinical signs. In victims, livers were paled and mottled, spleens dark and kidneys congested. No remarkable findings were seen in survivors.

The key acute inhalation toxicity study (BRRC 1990) was conducted according to a protocol similar to OECD Test Guideline 403, not in compliance with GLP. 3-Trimethoxysilylpropane-1-thiol did not cause any deaths in Sprague-Dawley rats following a six hour exposure to a saturated vapour of the test substance. The observed clinical signs of toxicity included slightly moist fur, periodic rubbing of head, eyes and nose during exposure, which were not evident at 1 hour post-exposure. No effects on body weight gain were observed. No other findings were reported.

Another two supporting acute inhalation toxicity studies were available, which did not meet current guideline requirements, but add supporting information for the endpoint and support the conclusion of the first study (DCC 1969, DCC 1963).


Justification for classification or non-classification

Based on the available data, 3-trimethoxysilylpropane-1-thiol is classified for acute oral toxicity according to Regulation (EC) 1272/2008 as Acute Oral Category 4; H302 Harmful if swallowed. No classification is proposed for acute dermal toxicity.