The elementary principle of reducing the risk of illness and injury from exposure to health hazards is to reduce the risk by reducing exposure. This could be accomplished by eliminating the hazard altogether. In industrial processes, this is not often reasonable, so substituting less harmful substances is more practical. Using less toxic materials and less hazardous processes requires knowledge of how chemicals react with each other and with the human body. This is where the science of toxicology can have the greatest impact: in helping prevent illness and injury. Toxicology can be defined as the science of poisons, in this case chemical toxins, and their effects on the human body. Toxicology is a relatively new science, and chemical toxicology is a very new part of toxicology. The student will investigate the state of the art of toxicology and of the harmfulness of chemicals.