Potent carcinogenicity of nitrosodiethanolamine in rats

Abstract

Nitrosodiethanolamine is found in synthetic cutting oils and in many cosmetic preparations and is probably the N-nitroso compound to which human exposure is greatest. It is formed by reaction of the commonly used amines diethanolamine and triethanolamine with nitrosating agents. An assessment of the possible risk in human exposure to nitrosodiethanolamine must be based on sound chronic toxicity data. The compound was administered at concentrations ranging from 3900-31,250 ppm in drinking water, to groups of rats for about 6 mo. When the animals were killed, all bore hepatocellular carcinomas, many of which metastasized at the higher doses, indicating that nitrosodiethanolamine is a carcinogen of considerable potency in the rat. It is inactive or very weakly active in short-term tests, such as the Ames Salmonella mutagenesis test.