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Description of key information

Acute toxicity tests with butyl benzyl phthalate in rats and mice (oral, up to 20 g/kg bw), rabbits (dermal, up to 10 g/kg bw), and rats (inhalation, saturated vapour) indicate that this compound does not need to be classified for acute toxicity.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
2 330 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:

Additional information

In a reliable study, butyl benzyl phthalate was assessed for acute oral toxicity in male and female F344/N rats and B6C3F1 mice (NTP, 1982). Groups of five rats and five mice of each sex were dosed with up to 20 g/kg bw by oral gavage, and surviving animals were observed for 14 days. Deaths occurred in rats at 2.5 g/kg bw and above and in mice at 5 g/kg bw and above. The LD50 value was estimated to be 2.33 g/kg bw for rats (of both sexes), 6.16 g/kg bw for male mice and 4.17 g/kg bw for female mice. These figures indicate that butyl benzyl phthalate is of low acute oral toxicity to rats and mice. This is supported by another rat study for which few details are available (hence it has been assigned reliability code 4), with an acute oral LD50 value of 20.4 g/kg bw (Birch, 1976a).


When neat Santicizer 160 (butyl benzyl phthalate) was applied to the skin of four New Zealand white rabbits at doses of around 4, 6 and 10 g/kg bw for an exposure period of 24 hours, there were no deaths in the subsequent 2 -week observation period, although the animals showed reductions in appetite and activity. [It is not clear which doses had these effects.] The viscera appeared normal on gross necropsy. The investigators concluded that the LD50 was greater than 10 g/kg bw (Birch, 1976b). Although details are only available in a brief summary report (hence it has been assigned reliability code 4), the data are considered adequate for assessment.

When four male rats were exposed for 6 hours to a saturated atmosphere containing Santicizer 160 (benzyl butyl phthalate) and observed for 3 days, there were no deaths and only mild transient effects, including irregular breathing, moderate lethargy and mild nasal irritation. There is no information provided on the actual test concentration (Younger, 1955).

Justification for classification or non-classification

Acute oral, dermal and inhalation toxicity studies on butyl benzyl phthalate are considered adequate for concluding that the compound does not need to be classified for acute toxicity, under the EU CLP Regulations.