In contrast to the blood lead level, which is an effective indicator of current exposure, the concentration of lead in the teeth is a measure of internal exposure in the past and low‐level chronic exposure. Our measurements show that lead concentrations depend in a complex manner on both the part and the type of tooth. We highlight a variety of risk factors of long‐term lead exposure: involuntary smoking (including by expecting mothers), the type and duration of the way to school (the effect of traffic), how children play, the individual environment (housing conditions), and other factors. ©1999 John Wiley & Sons, Inc. Environ Toxicol 14: 439–454, 1999