recent investigation by Reuters found that lead exposure affects kids in communities across the country — not just in high-profile cities like Flint, Michigan. This is worrisome, because elevated blood lead levels in kids have been linked to an array of developmental delays and behavioral problems. More ominously, this could also increase crime. Kevin Drum and others have argued that lead exposure caused the high crime rates during the 1980s and early 1990s. There has been suggestive evidence of such a link for decades, though it hasn’t gained much traction in research or policy circles. But the case that lead exposure causes crime recently became much stronger.