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Administrative data

Description of key information

Oral: LD50 = 3200 mg/kg body weight leading to no classification according to CLP

Dermal: LD50 > 5000 mg/kg body weight leading to no classification according to CLP

Inhalation: no information available

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
Only one key study is available. This GLP study is similar to OECD TG 401.

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
Only one study is available in whole database for the acute dermal toxicity. This GLP study is similar to OECD TG 402.

Additional information

- oral toxicity: The substance 4-phenylbutan-2-one is not acutely toxic to rats in a reliable and valid acute oral toxicity study and the oral LD50 value is 3200 mg/kg body weight (Moreno 1980). The supporting study (Tongbao 1980) reports an oral LD50 value of 1590 mg/kg body weight in mice, however, this result is considered as not reliable. Since this study has Klimisch 3 scoring, it is given a lower weight of evidence than the rat study.

- dermal toxicity: The substance 4-phenylbutan-2-one is not acutely toxic in a reliable and valid acute dermal toxicity study in rabbits with a dermal LD50 value > 5000 mg/kg body weight (Moreno 1980).

- inhalation toxicity: Information about the acute inhalation toxicity of the substance is not available.

Justification for selection of acute toxicity – oral endpoint

A reliable with restrictions key study similar to OECD TG 401.

Justification for selection of acute toxicity – dermal endpoint

A reliable with restrictions key study similar to OECD TG 402.

Justification for classification or non-classification

- oral toxicity:

Based on the above stated assessment of the acute oral toxicity of 4-phenylbutan-2-one, the results from reliable study are above the threshold value given in the CLP Regulation. Therefore 4-phenylbutan-2-one does not need to be classified according to Council Directive 2001/59/EC (28th ATP of Directive 67/548/EEC) and according to CLP (Regulation (EC) No 1272/2008 of the European Parliament and of the Council) as implementation of UN-GHS in the EU.

- dermal toxicity:

Based on the above stated assessment of the acute dermal toxicity, 4-phenylbutan-2-one does not need to be classified according to Council Directive 2001/59/EC (28th ATP of Directive 67/548/EEC) and according to CLP (Regulation (EC) No 1272/2008 of the European Parliament and of the Council) as implementation of UN-GHS in the EU.

- inhalation toxicity:

According to regulation (EC) 1907/2006 Annex XI (weight of evidence), testing for acute inhalation toxicity is not considered to be required, for the following reasons:

- 4-phenylbutan-2-one has a moderate vapour pressure of 5.6 Pa at 25°C, which corresponds to 5.6 Pa / 101325 Pa x 10e6 ppm = 55 ppm saturated vapour pressure corresponding to 333 mg/m³ or 0,33 mg/L (with a molecular weight of 148.2 g/mol). Thus an acute 4-hour inhalation study would either be carried out at 0.33 mg/L vapour or at the limit dose of 5 mg/L aerosol. Assuming a very conservative value of 100% bioavailability, a rat would receive a systemic dose of 0,8 L/min/kg x 240 min x 5 mg/L aerosol = 960 mg/kg.

- Since the acute oral LD50 was higher than this value, it is considered unlikely that mortality would be observed in an acute inhalation study.

- With regard to possible local respiratory effects, 4-phenylbutan-2-one is not classified for skin or eye irritation and showed no effects on skin and eyes. Therefore, 4-phenylbutan-2-one is considered unlikely to exert a relevant local irritative effect on respiratory mucosal membranes.

Therefore, performance of an acute inhalation study is considered not necessary for scientific reasons and 4-phenylbutan-2-one is considered unlikely to exert effects upon inhalation that would require classification according to Council Directive 2001/59/EC (28th ATP of Directive 67/548/EEC) and according to CLP (Regulation (EC) No. 1272/2008.