My cat kept peeing on the same rug for 6 months until I figured out it was the scent of the old cleaner.
It took me half a year and trying 4 different litter boxes before I realized she was marking over the citrus enzyme cleaner I used, so what other household smells set cats off?
My old roommate's cat would not go near the laundry room after she switched to a lavender detergent. We had to move the food bowl because the smell made him so nervous. I've also heard strong mint or pine scents from cleaners can do it. Cats have such sensitive noses, it's like they're living in a totally different world of smells.