Lead poisoning affects hundreds of thousands of U.S. youngsters, but most get it from paint chips and dust in deteriorating buildings ...

ATLANTA — Lead poisoning affects hundreds of thousands of U.S. youngsters, but most get it from paint chips and dust in deteriorating buildings — not recalled toys, U.S. health officials say.

Often, lead poisoning occurs with no obvious symptoms and frequently goes unrecognized. But it can cause irreversible learning disabilities and behavioral problems and, at very high levels, seizures, coma, and even death.

Dr. John Rosen, a lead poisoning specialist at the Children’s Hospital at Montefiore in New York City, said he recommends that if a child has been playing with a recalled toy for a month or more, parents should consider bringing the child in for a blood test.

About 310,000 U.S. children ages 1 to 5 have blood-lead levels that require treatment or other measures, according to the U.S. Centers for Disease Control and Prevention.

Lead-based paint was banned from use in housing in 1978, but young children are living in more than 4 million U.S. homes that have deteriorated leaded paint and elevated levels of lead-contaminated house dust, health officials estimate.