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Description of key information

The acute oral toxicity of Phthalic Acid is low. LD50 values >2000 mg/kg were reported in mice and rats.
In an acute inhalation study in rats, the aerolized test substance proved to have essentially no acute inhalation toxicity. The LC50 was >5058 mg/m³ in male and female rats.
There are no data on acute dermal toxicity available.

Key value for chemical safety assessment

Additional information

In a study conducted in male and female albino mice, an oral LD50 >5000 mg/kg bw was found (Schoneker, 2002).

In a second study in mice the LD50 was found to be 2530 mg/kg bw (Lin, 1982).

These values are supported by 2 studies in rats in which LD50 values were found to be 8000 and 7900 mg/kg respectively (Tomita, 1978; Giam, 1984), however the reliability of these studies can not be assessed due to limited documentation.

A study on the acute inhalation toxicity of Phthalic acid on rats has been conducted in accordance with the EU Directive 92/69/EEC, and especially OECD GD 403 (2009). One group of rats was nose-only exposed to powder aerosol in concentrations of 5058 mg/m³. The powder aerosol was generated so that it was respirable to rats. Mortality did not occur up the maximum technically attainable concentration. Rats exposed at 5058 mg/m³ displayed the following signs (exposure day up to second post exposure day): bradypnea, irregular breathing patterns, labored breathing patterns, nasal discharge (serous), nose: red encrustations, muzzle: red encrustations; motility reduced, limp, tremor, high-legged gait, lurching, piloerection, cyanosis, and hypothermia. The respirability of the aerosol was adequate, i.e. the mass median aerodynamic diameter (MMAD) was 3.1µm, the geometric standard deviation (GSD) was 1.9).

The results can be summarized as follows:

LC50 inhalation (powder aerosol, 4h), male/female rat: >5058 mg/m³.

NOAEL male and female rat: <5058 mg/m³

The aerolized test substance proved to have essentially no acute inhalation toxicity in rats (Pauluhn, 2009).

There are no data on acute dermal toxicity available.

Justification for classification or non-classification

Based on the available studies, the test substance needs no classification for acute toxicity according to EU guidelines.