AFAIK there has only been one documented case of it killing a kitten and it drank the liquid form, unknown quantity. Baby animals do not yet have fully formed livers to metabolize the sodium channel blocker. Insects on the other hand do not have a liver. They use body fat to detoxify but it isn't fast enough or volumetric enough to handle the sodium channel blocker in large amounts relative to their size.
People put dog tick/flea stuff on cats all the time by accident containing it (I've personally seen it twice now), it usually doesn't kill them but it's absolutely horrible to witness, cats will get seizures and treatment is only supportive, either they live or they don't. Both the cases I saw were brought to the vet and the cats were messed up pretty bad for a few days.
I could imagine if a cat was being covered in it often enough and they lick it up their glutathione may be depleted then their liver won't keep up. I will have to dig into the stats iskander provided to see pre-existing condition the cats were at. i.e. elderly, kittens, sickly Skimming over it I am not seeing stats on age or liver health.
AFAIK there has only been one documented case of it killing a kitten and it drank the liquid form, unknown quantity. Baby animals do not yet have fully formed livers to metabolize the sodium channel blocker. Insects on the other hand do not have a liver. They use body fat to detoxify but it isn't fast enough or volumetric enough to handle the sodium channel blocker in large amounts relative to their size.