How lead plumbing got pitched; National Lead Company ad from 1920s.
How standards for lead in water and blood got tighter as we learned more. Graph by Chris Sellers.
‘Air View of Chevrolet Motor Co. Plant, Flint, Mich.’, c.1930s, by Flickr user Don…The UpNorth Memories Guy… Harrison, CC BY-NC-ND 2.0.
All the cities you mention are basically "brown" spots - meaning large areas of the city is environmentally toxic due to years of industrial manufacturing. You can add Newark, New Jersey to the group. Urban planners and developers know all about these issues and don't discuss them openly.