N-nitroso-compounds form an important class of carcinogenic chemicals which may be of environmental importance (Druckrey et al. , 1967; Magee et al. , 1976; IARC, 1978). The mechanism by which these carcinogens initiate neoplastic growth is not well understood but there is substantial evidence favoring the hypothesis that the simple dialkylnitrosamines and alkylnitrosamides act by means of their conversion to al- kylating agents. Alkylating species are generated from the nitrosamines by metabolic activation and from the nitrosamides by chemical decomposition at physiological pH. It is widely...