Lead-poisoning threshold lowered by the CDC

Almost all children are exposed to lead, which does irreversible damage to the brain. While experts agree that there is no safe amount of lead exposure, the Centers for Disease Control and Prevention decided to toughen up its lead standards. The CDC announced last week that it had redefined the "action level" for lead exposure in children, USA Today reported. Under the CDC's previous guidelines, children only used to qualify for "action"–a.k.a. careful medical monitoring–if they had 10 micrograms per deciliter of lead in their blood. But the new threshold cuts that figure in half, to 5.

The CDC's decision means as many as 1 million children could be officially diagnosed with lead-poisoning, HealthDay reported. Under the old guidelines, the lead-poisoning number for kids was around 250,000.

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"This new definition of childhood lead poisoning will provide an enormous public health difference for all young children in the US, because it is evident that the prior level of 10 micrograms/deciliter did not protect the developing brains of young children," Dr. John Rosen told NPR. 

Most lead poisoning cases occur from lead-based paint, which was banned in 1978 but can still be found in old houses in poor neighborhoods, USA Today reported. It is also present in tap water. 

Some doctors say that young children should have their blood tested for lead. But a CDC report from January argues that preventing exposure to lead is more important than testing for it after the fact.