It’s been twenty years since lead was removed from household paint and gasoline, but millions of children in America are still living with dangerous levels of lead in their blood. Public health officials say it doesn’t have to be that way because lead poisoning is one of the most preventable of childhood illnesses. In the fourth and final part of our series. “The Silent Epidemic”, Deirdre Kennedy reports on the hidden sources of lead, and community efforts to protect children from exposure.