Disorders of the nervous system caused by exposure to specific physical and chemical agents were reviewed and discussed. Two basic forms of nervous system disorders discussed were axonal degeneration and segmental demyelination. Virtually all of the industrial toxicants that affect the peripheral nervous system cause a mixed sensorimotor peripheral neuropathy. While the manifestations are fairly consistent from one toxicant to another, certain specific characteristics are unique to individual agents. Physical agents that can have neurotoxic effects included electricity, noise, cumulative trauma disorders, extremes of temperature, magnetic fields, nonionizing radiation, ultrasound, and vibration. A variety of central nervous system (CNS) disorders may follow exposure to toxic chemicals. Acute exposure to a variety of agents may result in mild, typically reversible, CNS dysfunction or more severe acute toxic encephalopathy. In the earliest form of chronic toxicity, mild mood disorders predominate as the chief complaint. Typically depressive symptoms are observed and these are associated with sleep disturbances, loss of interest in normal activities, loss of sexual interest, loss of energy and increased fatigability, psychomotor slowing and diminished mental efficiency such as difficulty concentrating. An intermediate syndrome, mild chronic toxic encephalopathy seems to exist with more prominent manifestation of CNS impairment than those exhibited by persons with mood disorders alone. The role of neurotoxicants in the etiology of dementia was considered. Other neurologic syndromes, symptoms and signs discussed included Parkinson's disease, tremor, opsoclonus, seizure disorders, cranial neuropathy, tumors, and sacral neuropathy. Particularly hazardous exposures to lead (7439921), organic solvents, and pesticides were noted.