Historical perspective to a current controversy on the clinical spectrum of plumbism.

Concepts of health risk associated with lead usage have undergone profound change. In the past observations of the relationship between lead usage and lead poisoning were severely limited by lack of knowledge and the relatively small quantity of the metal used. The benefits of lead usage, when contrasted with the risk incurred, outweighed the known hazards. Industrial growth contributed to the increased interest in lead poisoning. A significant increase of workers at risk generated new interest in an old disease. A concept of control developed based upon the principle of a dose-response relationship. The old idea of benefit versus risk remained because technological society needed lead but agreed that by controlling the factory environment lead could be used safely. The criteria for injury remained climical plumbism. Growth and change in lead utilization, once again, brought lead hazard to the forefront. New applications distributed lead throughout the environment exposiing both workers and the general population. A segment of the scientific community now suggests that the old criteria to judge risk, clinical symptoms of plumbism, are inadequate.