'It was everywhere': how lead is poisoning America's poorest children

The toxin has endangered hundreds of thousands of kids. But parents in the hardest-hit neighborhoods may never be warned of the threat

Shanaya Ball did everything right during her pregnancy: she attended check-ups, ate well, and kitted out the nursery for her son Amari, who was born in March 2017.

But by his first birthday, Amari had failed to meet almost every developmental milestone, and was unable to play, communicate or move like other infants.