Years ago, lead was added to paint and varnish products that were widely used. Since 1978, lead has no longer been used in residential paint, but it is believed that about 24 million housing units in the United States currently have deteriorating lead paint and high levels of lead-contaminated house dust.
Health officials believe the major source of lead exposure among children in the U.S. comes from old lead-based paint and lead-contaminated dust found in buildings where painted surfaces have been allowed to deteriorate, such as in rental housing that is not well-maintained. Children living in older housing at or below the poverty line are at greatest risk. However, chipping, peeling, flaking lead-based paint is commonly found in old dwellings located in cities, but also can be found in suburban and rural areas, and children can be exposed in homes where renovations caused disturbance of old lead-based paint and dispersal of lead-contaminated dust.
Lead dust gets on children's hands and fingers during the normal activities of childhood, such as crawling on the floors of their home, or playing in soil around the outside of homes where exterior lead-based paint had flaked off. Older infants and toddlers are drawn to windows in rooms and those windows very often contain deteriorated lead-based paint. Small children put their fingers in their months, and many children tend to mouth toys, household furnishings, and horizontal surfaces such as porch railings or window sills. They can eat the dust or small chips of deteriorating lead-based paint without knowing it, and without their parents realizing it. Lead paint chips taste sweet and small children don't know that they are dangerous.