I had a look through the book and came across
22-102 (4)(5) ....
So, if a bathtub area is considered a class 1 location, then any equipment installed in the tub would have to be drip proof, weatherproof, watertight. But one could argue that the fan is actually in the attic....
Fan grills are designed to minimize splashing aswell.
GFIing the circuit is a possibility too.
