There are plenty of choices in organic types of kitty litter that would be less harmful than regular kitty litters, or not harmful at all, to your pets should they swallow the litter.
Some kitty litters are made of wheat, which cats are less likely to be allergic to than corn kitty litters. Litters can also be made from pine and cedar tree remnants, paper products as well as from nut shells.
Some of these organic litters are also available in clumping forms. This is convenient, as you know if you have ever cleaned a litter box, however, if you are concerned about your cat eating the litter then clumping is not what you want. As the article stated, the clumping litter could get caught in your cat's digestive system and cause serious problems.