It could be anything from work related solvents/paints etc to something in your fishing kit. Do you use any cleaners or solvents on your rods/grips. Your tacklebox/chillybin? The car steering wheel? Basically anything you handle before going fishing.
I've just spent the day staining the deck, and even after a shower still smell like paint Thats my excuse for not catching anything tonight even though the guys either side of me did.