In a lot of places there was also the issue of redlining and segregation. Places like Bill O'Reilly's famous Levittown, where he likes to say he learned him his solid family values and virtues, explicitly
forbade minorities from living there. So naturally, in many places, if you can't find housing where the white people are you end up finding it in the places where no one wants to live. And that's usually "on the other side of the tracks" where the factories are. This results in minorities living near pollution at a higher rate than whites. So it's not a conspiracy in the sense that whites want to make black people sick, it's that segregation results in black people getting sick, and white people didn't think that was a good enough reason to change the situation.