Women and their children wait for medication and instructions on how to use it at the clinic in Dareta, Nigeria. Treating children with high levels of lead is a painstaking process that works only if their environment at home is free from lead. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

Women and their children wait for medication and instructions on how to use it at the clinic in Dareta, Nigeria. Treating children with high levels of lead is a painstaking process that works only if their environment at home is free from lead. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR