I've had this high-pitched tone going since the mid to late 60's. Nothing seems to help, I have aids, and try to protect the remainder of my hearing. I'm afraid "The Warden" will have to put up with a profoundly deaf guy in another 20 years, or so (presuming she lets me live that long)
Farm equipment, heavy equipment, blasting, artillery, gunfire, routers, planers, table saws, and even skilsaws, didn't have anything to do with the problem, I'm sure
Good luck, and commiserating prayers sent for all afflicted.
