Despite years of concern about the toxic effects of high lead exposure and recent knowledge about the less apparent effects of exposure to low doses of lead, a total of 3 to 4 million children in the United States are still being exposed to concentrations of lead that could compromise their cognitive and social development. This paper discusses: (1) the long-term consequences of early exposure to lead; (2) prenatal exposure to lead; (3) definitions of a toxic dose of lead; and (4) reasons why little is being done to control lead exposure. In discussing the long-term effects of lead exposure, the report examines behavioral problems that often occur in children with exposures to low levels of lead and that may lead to children's failure in school. Data examined indicate that lead exposure is greater than average in groups in which subnormal intelligence, attention disorders, and behavior problems are found at higher than average rates; and that half of the black children living in poverty have elevated blood lead levels. Steps in a plan to prevent childhood lead poisoning, announced by the Centers for Disease Control in 1991, include an increase in the number of childhood lead poisoning prevention programs, effective abatement of leaded homes, and a national surveillance effort. (SM)