U.S. federal health officials have confirmed that young children in Flint, Michigan, had significantly higher levels of dangerous lead in their blood after the city switched its water supply from Detroit to the Flint River as a cost-cutting measure.
The city switched its water supply in 2014 without ensuring that water from the Flint River had been treated with anti-corrosive agents, as required by law. It corroded the city's old water mains, turning drinking water brown because of iron contamination, and also leached lead from smaller pipes that carried water into homes.
In all, nearly 100,000 people were affected by the contaminated water. Lead in water supplies can cause profound and permanent health problems, particularly in children whose brains and nervous systems are still developing.
"This crisis was entirely preventable and a startling reminder of the critical need to eliminate all sources of lead from our children's environment," Patrick Breysse, chief of environmental health at the U.S. Centers for Disease Control and Prevention, said Friday.
The CDC studied children younger than 6 — the age group most vulnerable to the effects of lead poisoning.
After a public outcry over the lead pollution, city managers switched their water source back to the city of Detroit's system. Subsequently, the study said, the percentage of children with high lead levels in their blood declined to what it had been before the diversion to Flint River supplies.
The study's authors said they did not take other factors into account, such as the possibility that some of the children may have ingested flakes of lead paint, which was once commonly used in many parts of the United States. They emphasized, however, that lead exposure affecting children remains a serious health concern not just in Flint, but across the United States.
Because the symptoms of lead exposure are not obvious at first, the CDC said, the problem frequently goes unrecognized. However, "even low levels of lead in children's blood have been shown to affect intelligence, ability to pay attention and academic achievement."
Several officials of the Michigan state government are facing criminal charges arising from the Flint water crisis.
The Detroit water that now courses through Flint's system does not pose the same corrosion problem. But until old pipes are replaced, Flint residents have been urged to drink only bottled water, and to use filters for drinking and cooking water, and for personal hygiene.