I have never worked in a manufacturing plant or industrial sit with many buildings. But maybe one day after college. Yourslef?
No I never have but I have heard bad things, what do you think?
Where I live in Syracuse , New York it has been proliferated since the 1870's. It seems to be bad, but still going 
Oh that is interesting, I wonder how they have been able to do it?
During like the 1900s, about 87 large industries were scattered in Syracuse.
Are there any other cluster of industries in the states?
No, it seems like a freaking cluster munition though with all the explosive weapon sounding noise though.