Exposure to lead at an early age has been linked to cognitive impairment and behavioral problems, which is why the stories about officials allegedly covering up excessive lead in the water supply of Flint, Michigan, became a national scandal. But an alarming 2016 Reuters investigation documenting children’s exposure to lead in 21 states, including California, never got the attention it deserved. In Flint, 5 percent of children met the Centers for Disease Control elevated lead exposure threshold of 5 micrograms per deciliter of blood, double the national average.