Registration Dossier

Administrative data

Description of key information

Acute oral toxicity (similar to OECD 401): LD50>5000 mg/kg bw (BASF 1983; 83/186)
Acute inhalation toxicity (IHT): No mortality after 7h exposure of a vapor saturated atmosphere (BASF1993;10I0358/927012).
Acute dermal toxicity (similar to OECD 402): LD50>2000 mg/kg bw (BASF 1984; 83/186)

Key value for chemical safety assessment

Additional information

Acute oral toxicity

In the chosen key study for acute oral toxicity, i.e. an internal acute toxicity test similar to OECD 401, 5 Wistar rats per sex were treated via a single oral dose (gavage) with 2150, 3160 and 5000 mg/kg tetrahydro-2-isobutyl-4-methyl-2H-pyran (BASF 1983; 83/186). Test substance related mortality has been observed in 1/10 animals at 5000 mg/kg bw only. The LD50 has been reported to be >5000 mg/kg bw. Therefore tetrahydro-2-isobutyl-4-methyl-2H-pyran was found to be virtually non-toxic after single oral administration.

 

Acute inhalation toxicity

No key study is available for acite inhalation toxicity of . In a supportive study, i.e. an inhalation hazard test, 3 Wistar rats per sex were exposed (whole body) to a vapor saturated atmosphere with a nominal concentration of 23.1 mg/l tetrahydro-2-isobutyl-4-methyl-2H-pyran (not verified analytically) for 7 hours (BASF1993;10I0358/927012). No mortality was observed and eyelid closure and accelerated respiration at the beginning of exposure were the only clinical signs detected. Therefore, the inhalation of a highly saturated vapor-air mixture of tetrahydro-2-isobutyl-4-methyl-2H-pyran represents no acute hazard.

For the coverage of a second and human relevant route of exposure, a study on acute dermal toxicity is available (see below). Overall, an acute toxicity study via the inhalative route is scientifically not required and would not be in line with animal welfare requirements.  

 

Acute dermal toxicity

In the chosen key study for acute dermal toxicity, i.e. an internal acute toxicity test similar to OECD 402, 5 Wistar rats per sex were treated via a single dermal (semiocclusive) application of undiluted tetrahydro-2-isobutyl-4-methyl-2H-pyran (2000 mg/kg) for 4 hours (BASF 1984; 83/186). No test substance related mortality has been observed. The LD50 has been reported to be >2000 mg/kg bw. Therefore tetrahydro-2-isobutyl-4-methyl-2H-pyran was found to be virtually non-toxic after single dermal administration.

Justification for classification or non-classification

The present data on acute oral and dermal toxicity do not fulfill the criteria laid down in regulation (EU) 1272/2008, and therefore, a non-classification is warranted.