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Cat Health Problems and Clumping Clay Kitty Litters

By Marina Michaels

Overview: Clumping clay kitty litters may be related to a wide variety of seemingly unrelated cat health problems, included diarrhea, mega-bowel or mega-colon syndrome, unexplained lethargy, unexplained vomiting (especially frothy yellow vomit), irritable bowel syndrome, kidney diseases, respiratory problems, eye problems, general failure to thrive, anemia, and even death. This page provides supporting data for people who have read my article on the potential health hazards of clumping clay kitty litters and who want more data.

Occasionally, I receive email from people who have read my article on the potential health hazards of clumping clay kitty litters and who want more data, or who want to see some studies. I understand that some people may be skeptical if they only read of my experiences. I also understand that some people just Need More Data. :-) To help those people out, I created this page that organizes a number of links so you can go gather data as desired. These links lead to a large amount of data, though, so be prepared to spend hours wading through it all.

1. General Notes

At least two of the clumping litter companies themselves have said not to use the clumping litters with young kittens and to not allow your cats to eat the material (as if there were some way to keep cats from grooming themselves with their tongues). Would it be speculation to say that they know there is a problem? The ASPCA of New York also specifically recommends against using scoopable/clumping clay litters with kittens under two months of age.

Also, there are a number of veterinarians and health technicians who have experienced the same problems in their practice (I have heard directly from some of them, or indirectly from some of their clients), and there have been some autopsies confirming problems caused by impacted clumping clay litter. Several vets have links to my article at their Web sites.

Not just housecats suffer health problems. Rabbits are even more susceptible to these litters, since they groom themselves more assiduously. From hrssandi@halcyon.com of the House Rabbit Society, I discovered that rabbit deaths have been reported from clumping/scoopable cat litters "since before 1988. . . . In rabbits, some of the autopsies have shown that their intestines have actually been cut by this stuff as it tries to pass through . . . other deaths are as you've described in cats." The House Rabbit Society also warns: "clumping litters will clump inside the rabbit's digestive and respiratory tracts (the latter if they manage to make enough dust to breathe) causing serious problems and often leading to death."

Ferrets too are especially susceptible to nose blockages (and possible death) from clumping litters, as well as other possible problems from ingesting the litter.

2. A study by the Hennepin Poison Control Center

A few excerpts from a study done by the Hennepin Center for Poison Control, Minnesota on sodium bentonite (the material that makes clumping clay kitty litters clump). One of the authors of the study kindly provided me with a copy of the study, titled "Suspected bentonite toxicosis in a cat from ingestion of clay cat litter," by Carl S. Hornfeldt MS, ABAT, Hennepin Regional Poison Control Center, and Michael L. Westfall, DVM, Hudson Road Animal Hospital PA, originally published in Vet. Human Toxicology 38 (5) October 1996, pages 365-366.

"ABSTRACT. A 2 1/2-y-old spayed female cat was presented for lethargy and weakness. The cat was hypokalemic (3.1mEq K/L) and severely anemic (60% PVC, 1.3 g hemoglobin/dl). The cat was known to ingest bentonite-containing cat litter. It recovered with treatment of IV fluids, electrolytes and whole blood transfusion and was discharged. Two months later the cat was presented again with signs similar to those seen previously. This occurred 1 mo after the owner resumed the use of bentonite-containing cat litter. The signs were remarkably similar to those reported in humans from the chronic ingestion of bentonite clays. Bentonite toxicosis is suggested by the coexistence of hypokalemia hypochromic anemia in cats presented with lethargy and muscle weakness."
"...radiography revealed small masses of radiopaque material throughout the colon."
"DISCUSSION. The chronic ingestion of bentonite-containing cat litter by this cat appeared associated with hypokalemia, lethargy and muscle weakness, dehydration and heart murmur in addition to macrocytic hypochromic anemia. Clinical signs quickly resolved with administration of fluids and whole blood and removal from the cat litter. Poisoning from the chronic ingestion of bentonite clay has been reported in humans (1-3). ... Given the common use of bentonite clay litters for cats, veterinarians should consider bentonite toxicity when a cat is presented for lethargy, weakness and coexisting hypokalemia and anemia."

There's lots more. Emphasis in excerpts mine. You can find the full text of this article here.

3. Excerpts From Letters I've Received

This page has excerpts from letters I've received, including from some health professionals:

http://www.thelighthouseonline.com/letters/letters.html

How about some letters sent to the SWheatScoop Company?

4. More Articles on the Same Topic

Here is an article written by a health professional about her experiences:

http://www.felinesandfriends.org/content/clumping.htm

And here are a couple more articles:

Pet Consumer Report
E-Magazine
If you have a bird, avoid using clumping clay kitty litters as a cage liner. (Scroll to the very bottom of this link to find the information.)

5. What Exactly is Sodium Bentonite Good For, Anyway?

Because it swells so much (15 to 18 times its dry size) and adheres together with other particles of itself, sodium bentonite is used to seal dams. Great for dams. Bad inside a cat. It is also used as a grouting, sealing, and plugging material, a gellant, and a viscosifier, to seal ponds, basements, and so on. These uses do not sound like sodium bentonite is a good candidate for ingestion. Check out these representative links for more:

http://www.clayresources.com.au/dam_sealing.html ("Sodium bentonite is a naturally occurring clay material composed predominantly of the active constituent montmorillonite. On exposure to water, bentonite exhibits high swelling properties. Use is made of this in the sealing of porous soils where the swollen mass fills the voids and binds the soil particles to create an impermeable seal.")

http://www.cetco.com/groups/lining_main.asp ("unique self-healing sodium bentonite base"—sounds like, once it forms its wonderful seal, ain't nothin' goin' to get into it—or out—including nourishment once there is such a seal inside a cat)

http://www.basementsolutions.com/Injection.htm ("Injection of waterproofing substances into exterior. ... sodium bentonite or another substance—sold under a variety of trade names—is injected into the space between the soil mass and the basement wall. It swells to many times its dry volume when it is first put into slurry form. The slurry will tend to penetrate and plug cracks where water might also find a path to the basement interior, thus reducing the flow of water.")

http://www.baroididp.com/MSDSlist.htm (lists one company's products containing sodium bentonite and what they are used for). Their untreated sodium bentonite "After hydration, forms a semi-solid, flexible seal with permeability less than 1 x 10-8 cm/sec." A friend of mine studying pre-med raised the question of how this might affect the delicate permeable membranes of the kidneys.

A link sent in by a reader: http://www.texassodiumbentonite.com/.

Sodium bentonite contains aluminum and is used in some pet foods, especially dog foods. Read the label! Aluminum itself, of course, is a health hazard as well.

6. How About a Material Safety Data Sheet?

I have in my files a material safety data sheet on sodium bentonite that states that ingesting or inhaling the substance is hazardous to human health. If it is hazardous to humans, wouldn't it also be hazardous to cats? .

Conclusion

The bottom line is that there is enough evidence that clumping litters can cause a range of health problems in cats (and other animals), and there are enough safe alternatives, that it doesn't make sense to use a clumping litter.