Eighty percent of cancer is related to the environment.

Five reasons lead us to believe that much of cancer is environmentally related: 1. Beginning with the work of Yamagiwa and Ichikawa in 1915, cancer has been produced in the laboratory under the control of man. 2. The trends of cancer incidence (and mortality) have been sharply up in some cases (lung), and sharply down in others (stomach, uterine cervix). 3. There are large differences in cancer among different parts of the world, and within the United States. 4. Migrants from one part of the world to another take on the rates of the part of the world to which they migrate. 5. Removal of known causes from the environment has been followed by reduced cancer incidence. Environmental causes of cancer lie in both personal environment: cigarette smoking, use of alcohol, sexual habits, perhaps diet; and in the impersonal environment: industrial and occupational pollutants, water and air contaminants, pesticides, flame retardants, diet additives, drugs. A joint effort by persons and by governments can reduce the incidence of cancer.