For the first time in 20 years, federal health authorities have lowered the recommended limit for lead exposure in young children, which they say could add 200,000 children to those believed to have unsafe lead levels in their blood.
The new standard, announced by the Centers for Disease Control and Prevention on Wednesday and applicable to children under 6, lowers the threshold to 5 micrograms of lead per deciliter of blood, from 10 micrograms per deciliter.
High lead levels in young children have been found to affect cognitive development and may lead to a lower I.Q.