Registration Dossier

Diss Factsheets

Toxicological information

Carcinogenicity

Currently viewing:

Administrative data

Description of key information

Key value for chemical safety assessment

Justification for classification or non-classification

Classification concerning carcinogenicity is not warranted.

Additional information

The carcinogenic potential of isobutyraldehyde was examined in two rodents studies.

A 2-year inhalation study was reported (NTP, 1999). In this study (done with NTP standards), male and female rats were given vapour concentrations of 500, 1000 and 2000 ppm (= 1.5, 3 and 6 mg/l). No increase in neoplasm incidences that could be attributed to exposure to isobutyraldehyde was observed in male or female rats. Non-neoplastic lesions related to isobutyraldehyde exposure were limited to the nose and consisted of squamous metaplasia of the respiratory epithelium, degeneration of the olfactory epithelium, and suppurative inflammation. Incidences of minimal to mild squamous metaplasia in 1000 and 2000 ppm males and females and in 500 ppm females were significantly greater than those in the chamber controls. Minimal to mild degeneration of the olfactory epithelium occurred in the 2000 ppm males and females. Incidences of suppurative inflammation (rhinitis) in both sexes exposed to 2000 ppm were increased compared to controls. The LOAEC was found to be 500 ppm.

Another 2-year inhalation study (NTP, 1999) using male and female mice showed also a negative result. Mice were given vapour concentrations of 500, 1000 and 2000 ppm (= 1.5, 3 and 6 mg/l). No neoplasms that could be attributed to isobutyraldehyde exposure were observed in either males or females. Non-neoplastic lesions related to isobutyraldehyde exposure were limited to the nose. The incidences of olfactory epithelial degeneration in 1000 and 2000 ppm males and females were significantly greater than in the chamber controls. The NOAEC was found to be 500 ppm. This study was done with NTP-standards.