When I mentioned this to my wife who is from KY and saw the same tanks in Bardstown, she mentioned that a few years ago the residents of Smithfield, KY had run off the distillers who wanted to put a couple of tanks in their area. They cited the black gunk that got onto everything. Here's an article about Shively, KY with some interesting pics of black fungus on cars, signs, everywhere it seems, not just on the tanks. https://www.vice.com/en_us/article/78dyqb/kentuckys-whiskey-fungus-problem-is-out-of-control
That's very interesting too.