Zoning isn't needed just for low and high noise.
You also have to consider factors like industrial safety. For example, fertilizer[1] and pesticide[2] plants must be built a certain distance away from populated areas. There are, of course, many other industrial processes that also require a safety perimeter, but those are two that come immediately to mind.
[1] https://en.wikipedia.org/wiki/West_Fertilizer_Company_explos...