Cat Litter: Are Clumping Varieties Safe?

There Are Health Concerns Surrounding Clumping Clay Litters

Clumping litters are common, but many varieties include controversial ingredients. Cat Attract, a popular version, uses sodium bentonite for its clumping abilities.There are concerns about the ingredients impact on digestive systems, but scientific proof of the link has been unavailable. 

Where Did the Clumping Claw Controversy Originate?

The whole furor over clumping clay  apparently originated on the website of one individual, Marina McInnis,  in her article, Clumping Clay Litters: a Deadly Convenience?

McInnis is a breeder who tragically lost litters of kittens in the mid-1990s. She later determined that the cause was the ingestion of clumping clay litter, which caused intestinal blockage from the clumping clay. In her original article, she cited confirmation from her own holistic veterinarian, along with supporting information from another holistic health practitioner. Ms. McInnis also cited communication with another breeder who had encountered similar problems, confirmed with that breeder's holistic veterinarian. 

To back up her own experiences, McInnis includes letters from readers who reported similar problems with their own cats. Some of the letters referred to the writers' veterinarians or laboratories finding clay in stools of cats with bowel problems, but no confirmation from veterinarians was listed. The most compelling evidence Marina McInnis presented, other than her own anecdotal experience, was a reprint of an article on suspected Bentonite toxicosis, which originally appeared in the Journal of Veterinary and Human Toxicology in June 1997.

Even that article resulted in a critical letter by another veterinarian - the full exchange can also be read on McInnis's website. 

Personal Stories and Proof

Much of the controversy has arisen from personal stories, rather than scientific evidence. Not surprisingly, certain "premium" cat litter manufacturers have been able to use the clumping clay controversy to their advantage in promoting their own "safe" clumping litters.

On the other side of the coin, I have found few articles alluding to the safety of sodium bentonite in cat litter, other than by those manufacturers that still use it, such as Cat Attract and Simplicity.

Next > The rise and fall of clumping clay litters 

In the "olden days," litter boxes were homemade affairs, and the substrate used was anything at hand that the cat might dig into and use. Sand was popular if it could be easily sourced; garden dirt was a natural - after all, most cats were indoors-outdoors, and that is where they usually "did their business. Shredded newspaper was another.

Then, in the late 1940s, Edward Lowe, a young man who worked in his dad's company, which sold industrial absorbents, gave a neighbor a supply of an absorbent called Fuller's Earth to replace the ashes she was using in her cat's litter box.

She was so "sold" on the clay that Lowe started marketing it as "Kitty Litter," first through pet stores, then by going to cat shows and cleaning cat boxes in exchange for a booth to market his product. "Kitty Litter" became immensely popular and a new industry was born.

Forty years later, "scoopable" clay litters containing sodium bentonite came on the market and were an instant success. Traditional clay litters had to be replaced frequently; with scoopable litter, one had only to scoop out the solids and the clumps of urine and add a small amount of fresh litter. The box would last up to a month without completely replacing the used litter.

Six or seven years later, it began to appear that these scoopable clay litters  might have a downside. The arguments for potential hazards to pets of using clumping clay with sodium bentonite certainly sound logical:

  • Cats inhale dust from clay litter or ingest it while cleaning their feet. Kittens, being curious creatures, sometimes eat litter.
  • The powerful clumping abilities of sodium betonite cause the ingested clay dust and particles which, when combined with natural and ingested liquid form a solid mass. (When liquid is added, bentonite swells to approximately 15 times its original volume, as quoted from Cat Fancy magazine in the McInnis article.)
  • Inhaled particles could cause similar problems in the moist climate of the lungs. (The dust in clay is silica dust, which is not particularly friendly to either human or feline lungs.) 
  • The "clumping activity" in the intestines could draw fluid out of the body, causing dehydration, and possibly consequential urinary tract problems.
  •  The clumping substance coats the digestive tract,"attracting the collection of old fecal material, increasing toxicity, bacteria growth and prohibiting proper assimilation of digested food. This can lead to stress on the immune system, leaving the animal susceptible to viral, bacterial, parasitic and yeast infections." (From an article by Lisa Newman.)
  • The problems can also extend to dogs, who sometimes are inexplicably drawn to "litter box snacks." 

Absent any scientific studies or documented cases, it is hard to make an objective decision about the use of clumping clay litters for our cats. However, since there are a number of alternative litters that do not use sodium bentonite, the prudent cat caregiver would consider using one of those as an alternative. I would suggest that those consumers who are happy with their choice of scoopable clay litters follow a couple of guidelines:

  1. Do not use them for kittens. Since the curious little tykes investigate everything first with their mouths, why take chances on their ingesting something that is potentially harmful?
  2. If you see an older cat eating litter, get him to the veterinarian. Eating mineral substances such as clay is a sign of pica, which can indicate a nutritional imbalance.
  3. If your cat develops sudden stomach problems, constipation, diarrhea, coughing, or discomfort during urination, mention to your veterinarian that you are using a clumping clay litter.

One thing is certain: Ed Lowe certainly was unaware of the can of worms that would open over 50 years after he invented kitty litter. He died in 1995, shortly before the first rumors erupted about the hazards of clumping clay litter. And the controversy continues.