Cancer

Malignant tumours. It is now generally assumed that cancer can be caused by certain chemical substances, by certain physical effects and by viruses. Particular attention is directed at cancer-producing substances (carcinogens) in the environmental debate. These substances can be of both natural (e.g. Aflatoxins) and civilization-derived origin. Substances with clearly carcinogenic characteristics include the Polycylic Aromatic Hydrocarbons (e.g. Benzpyrene), Benzene, Asbestos, and the salts of chromium, beryllium, silver and Mercury, and certain Pesticides (DDT, aldrin, dieldrin, etc.).