Children are most often poisoned by lead that comes from old lead-based paint. Although lead-based paint has been banned for residential use since 1960 in New York City and since 1978 in the rest of New York State and the country, most older housing has at least some old layers of lead paint. Typically, lead paint was used on kitchen and bathroom walls and throughout homes on doors, windows and wooden trim.3 Nationally, 20% of all housing built between 1959 and 1974 has some lead paint, 70% of housing built between 1940 and 1959 has some lead paint, and 99% of housing built before 1940 has some lead paint.5 In addition, the lead paint manufactured from the late 1800's until about the 1940's tended to have much higher lead content -- up to fifty percent lead -- than the lead paint that was produced later. Today, paint that contains 0.06 percent or more of lead by weight is banned for residential use in New York State.4
The most common cause of lead poisoning in young children is ingesting house dust that is contaminated with lead from lead paint. If the paint is in poor condition, chipping, peeling and flaking, it can be ground into dust after it falls to the floor. Lead paint on the sliding parts of windows may be ground up into dust when you open or close the windows. Any lead-painted surface that gets worn away as it is used (door edges, door jambs, cabinet door edges) or worn away when it's walked on (painted floors and stair steps) can be a source of lead-contaminated house dust.
As every parent knows, it is normal for babies and toddlers to put things in their mouths -- their hands, their toys, almost anything they can fit. The lead-contaminated dust gets on the children's hands or their toys and then into their mouths; this may happen repeatedly, adding up to a significant lead exposure. Children can also inhale lead-contaminated dust that has been raised up by dry sweeping and dry dusting. They may also ingest lead-contaminated dust that has settled onto foods that are stored uncovered on shelves and counters. Very young children may chew on painted objects around them, including the edges of windowsills, doors, chair rails, even painted pipes and radiators when they're not too hot. If these items were painted with lead paint, children may swallow particles or chips of lead paint from these "chewable" surfaces. Some children may pick up and eat loose paint chips they happen to find.
The effects of lead poisoning vary with the amount of lead absorbed into the body, the duration of the exposure, and the age and developmental stage of the child. Even mild lead poisoning can decrease children's intelligence and affect their neurobehavioral development, growth, and hearing. At somewhat higher exposures, lead damages the central nervous system and kidneys and interferes with blood cell formation and development. Very severe exposures can cause coma, convulsions and even death; fortunately, lead poisoning this severe is now extremely rare. However, the damage caused by even mild lead poisoning may be permanent. It is not yet known how much, if any, of the damage can be reversed, even when the exposure to lead is discovered early and eliminated quickly. That is why it is so important to protect young children from being exposed to lead in the first place.
Most lead-poisoned children will not have any obvious symptoms. Children poisoned by lead when they were preschoolers may not show any problems until they are in school, when reading disabilities and problems with attention and fine motor coordination may become apparent. Children with a history of lead poisoning may have greater absenteeism from school, lower class ranking, and a higher risk of not graduating from high school.6
Preschool-aged children are most at risk of becoming poisoned by lead, for several reasons. Very young children tend to have higher exposures to lead because of their normal mouthing and hand-to-mouth behavior. Very young children also absorb lead more efficiently than adults; they may absorb four times more of the lead they swallow than an adult swallowing the same amount of lead. Finally, very young children are more susceptible to the effects of lead because they are still rapidly growing and developing.