Performs work requiring professional knowledge of toxicology. Studies adverse effects of chemical substances or similar agents on living organisms and/or the environment, and assesses the probability of their occurrence under specified conditions of use or exposure. Studies interactions of chemical and physical agents and biological systems. Explores nature and mechanisms of adverse reactions and assesses the likelihood that adverse effects will occur. Requires scientific knowledge that includes pathology, anatomy, chemistry, biochemistry, microbiology, physiology, pharmacology, toxicology, and materials sciences but does not require full preparation for practice in any one of those disciplines or full professional training in medicine or veterinary medicine.