Environmental carcinogenesis and cancers.

I. T H E N A T U R E AND SCOPE OF E N V I R O N M E N T A L CANCER HAZARDS Almost ~00 years have passed since the first environmental carcinogen, coal soot, was recognized as the cause of cancer of the human skin. The environmental carcinogenic spectrum composed of accepted, suspected, and potentially carcinogenic agents present in the natural and artificial human environment has grown considerably during the intervening years. Despite the impressive increase therefrom, resulting in the number, diversity, and spread of environmental cancer hazards among the general and especially the industrially employed and urban populations and despite the ready availability of an abundant amount of reliable facts and observations on the causation of human cancers by environmental agents, governmental, private, and professional parties directly concerned with the protection and maintenance of human health have displayed until recently an astounding indifference and aloofness toward this important aspect of the general cancer problem. A partial awakening from this general state of lethargy has, however, occurred during the last decade because of the impact produced by the strong reaction of the general public to widely disseminated information relative to the increasing and probably dangerous contamination of the human environment and of many products of daily consumption with carcinogenic agents. This rising concern with mainly industry-related environmental cancer hazard was aroused by three recent developments: 1. The growing contamination of air, water, and soil as well as of foodstuffs with radioactive mat ter from activities in the nuclear energy field. ~. The increasing pollution of the inhaled air with various chemical carcinogens contained in in-