Catty1,

Tanned leather uses many caustic chemicals most are removed by the time the product is finished but residues may remain. Other items may be coloring stains, softeners, stain protectors (scotch guard). Take a damp white towel and rub the leather to see if anything comes off, if it does that is what the cat may be ingesting. Good luck, we can’t have leather furniture for fear that our cats would ruin it; in fact we can’t have anything nice (bad cats).

Good luck and best of wishes.