You folks are good! I got the answer from you before anyone even posted a comment!
Minutes after writing the previous post I remembered that I had a plastic jar of muriatic acid I kept in the shop. I used it for sharpening files.
I remembered that I kept it stored on a shelf along the wall by my bench.
To my surprise there was a crack in the lid of the jar! I am surprised I did not notice any fumes because muriatic acid is extremely noxious and obnoxious. I only use it out side the house.
I am pretty sure that enough fumes must have been escaping to cause corrosion on the tools stored over the bench. This must be why tools on the other side of the shop were not getting rusty.
I’m sure the muriatic acid fumes leaking into the shop were not doing me any good either!
Time to take the rust off my chisels and saws now….