ABSTRACT
The past century has seen a tremendous expansion in the number of synthetic chemicals employed by humankind as materials, drugs, preservatives for foods and other products, pesticides, cleaning agents, and even weapons of war. An estimated 64,000 chemicals are currently in use commercially, with 5 billion tons being produced annually in the world. Some 4000 chemicals are used as medicinals and at least 1200 more as household products. An estimated 700 new chemicals are synthesized each year. Add to this the numerous natural substances, both inorganic and organic, that possess toxic potential, and it is little wonder that the public expresses concern and even, sometimes, panic about the harmful effects these agents may exert on their health and on the environment. Many of these agents, perhaps 50,000 of them, have never been subjected to a thorough toxicity testing.
