Carcinogenicity of N-nitroso-acetoxymethyl-methylamine (acetoxymethyl-methylnitrosamine) after inhalation in rats.

Inhalation of nitroso-acetoxymethyl-methylamine (NAMMA) at a mean concentration of 0.5 ppm (= 2.6 mg/m3), 5 h/day, 5 days/week for 7 weeks proved to be highly toxic and carcinogenic in male Sprague-Dawley rats. The first tumour (a carcinoma of the lung) developed after a 14-day period of carcinogen application. The nasal region and the trachea were found to be the main target organs for the local carcinogenic activity.