Registration Dossier

Administrative data

Description of key information

TMQ is of low acute  toxicity by the oral and the dermal route of exposure.
There are no studies available which evaluate acute inhalation toxicity.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
3 190 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
5 010 mg/kg bw

Additional information

In an early study with limited documentation groups of 5 male and 5 female albino rats were dosed with TMQ in an acute oral toxicity experiment. Animals were dosed with 2160 to 4470 mg/kg and observed for 14 days. Clinical signs as sluggishness was recorded to start 48 h after dosing; death occurred during the second to fourth day after treatment. The calculated LD50 was 3190 mg/kg (95% CL 2730 -3720 mg/kg; de Groot, 1976). Additional acute oral studies cited briefly in the database support the conclusion that TMQ is of low acute oral toxicity with LD50 values above 2000 mg/kg.

In an early dermal study with limited documentation one rabbit was dosed with 5010 mg/kg bw and two rabbits were dosed with 7940 mg/kg . Animals were observed for 14 days. Clinical signs were noted for all animals and gross autopsy of the survivors indicated hemorrhagic areas of the lung, discoloration of liver, spleen and kidney and inflammation of the gastrointestinal tract. The rabbit in the low dose group survived and one out of two rabbits in the high dose group died after 4 days. No precise LD50 value can be calculated but a cut-off LD50 can be estimated to be > 5010 mg/kg bw (D. Birch 1976).

Justification for classification or non-classification

Based on the available information no classification is required according to the EU classification criteria 67/548/EWG and regulation no. 1272/2008 (GHS).