Titanium dioxide (1990)

Abstract

Titanium dioxide was of low skin and eye irritancy in rabbits. A low acute oral, dermal and inhalation toxicity was indicated in laboratory animals. Long-term feeding studies in rodents could identify no specific site of toxic action and generated no convincing evidence of carcinogenicity. The direct administration of titanium dioxide into the respiratory tract of rats, rabbits and dogs produced lung injury. Lifetime inhalation studies in rats indicated toxic and carcinogenic effects in the lungs. Limited studies in hamsters involving direct instillation into the respiratory tract found no evidence of carcinogenic activity, although titanium dioxide was shown to enhance the action of a known carcinogen. A range of genotoxicity assays including the Ames bacterial test failed to detect activity.

Information on inhalation toxicity in man is sparse; lung changes have been recorded in a number of individuals. An initial report from a more systematic study of a titanium dioxide-exposed workforce provided no evidence of an effect on the lung, and overall cancer rates were normal. No evidence of a skin sensitizing action was seen in a group of dermatitis patients.