NEW YORK -- Health officials say more than half a million young children are now believed to have lead poisoning in the United States.
The figure is roughly twice the previous high estimate. But that's because the government last year lowered the threshold for lead poisoning, so now more children are considered at risk.
Too much lead can be harmful to developing brains and can mean a lower IQ. The new number released Thursday translates to about 1 in 38 young children.
After lowering the standard, the government went back and looked at blood tests from children under 6 to determine how many have lead poisoning under the new definition.
Lead poisoning has been a waning concern, as leaded gasoline, paint and other sources have diminished.