Respectful of Otters suggests why the imagined crisis of "crack babies" gets so much more attention than the very real crisis of lead babies:

The lead problem is complex; it implicates delinquent landlords, decaying inner city housing stock, the shift in low-income housing assistance from federally maintained properties to the Section 8 system (which relies on private landlords), and state and municipal governments. That complexity just didn't fit in with the 80s and 90s zeitgeist in which the problems of the poor were blamed on individual pathology. In contrast, the "crack baby epidemic" was about poor black women being bad mothers, individually to blame for putting their babies at risk.