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Parents around the country have voiced alarm since the 2015 revelations of staggeringly high lead levels in the drinking water of Flint, and more recent reports of spikes in other cities and states. It is easy to understand why people are upset. "Children are particularly vulnerable to the neurotoxic effects of lead," states the World Health Organization on its Web site. It goes on: " Even relatively low levels of exposure can cause serious and in some cases irreversible neurological damage. " After learning that Flint’s water was tainted, some medical professionals have said the lead would permanently harm young brains and possibly other organs. Personal injury attorneys, pressing lawsuits, use phrases such as "irreparable damage" and "lead poisoning".
   Yet the Flint children and others like them are not doomed. The WHO statement uses words like "relatively" and "can" , but it does not say damage is certain. Water lead levels in Flint were extremely high, and blood lead levels did rise after the exposure. But experts involved in setting lead-exposure standards say the blood levels linked to Flint — thought to have peaked between five and 10 micrograms per deciliter (g/dL) in most cases, although exact numbers have not been made public — generally do not result in permanent neurological deficits. There is even evidence that an anatomical feature called the blood-brain barrier may keep low levels of lead from entering brain cells.