Daily Footprint, #30 – Sustainable and Ethical Cat Litter

Hi folks! I’m going to take a look at the social and environmental impact of cat litter, which provides a good example of why we need user-generated reviews. I think that most people want to make ethical choices, but researching the sustainability of something like kitty litter never quite becomes a priority. Green stars reviews on public sites make information that a few people have time to find available to many (like all user-generated content, from Wikipedia to Yelp). If you haven’t seen it, here’s a post on why I believe user-generated content is the best medium for ethical consumerism guidance.

What is cat litter made from?

In comparing sustainability of cat litter brands, a large part of it comes down to the materials used. Many of the best-selling cat litters from Nestlé (Purina), Church & Dwight (Arm and Hammer) or Clorox (Fresh Step, Scoop Away, Ever Clean) are made from bentonite clay or silica gel crystals. Bentonite clay is mined from the earth while silica gel is made from sand. Both sound “natural” enough but neither is renewable and extraction of both impacts their environment. These litters could also cause health problems if regularly licked off paws, as they can swell to up to 15 times their original size in your kitty’s stomach.

Alternatives to clay and crystal cat litter

This article by a vet discusses alternatives to litter made from clay or crystals and recommends walnut shells, recycled paper, pine wood, and grass. Here’s another article on litter alternatives that adds bamboo and coconut fiber to the list.

Bentonite clay versus walnut shells

I used to use Ever Clean cat litter – well, not me personally, but you know what I mean. I figured: it’s made from clay and comes in a cardboard box; Good enough. It wasn’t until other brands started emerging that I questioned whether I could do better. I switched from Ever Clean to Naturally Fresh, litter that’s made from walnut shell waste generated here in California. A little bit of research into bentonite clay (used for clumping clay litter) convinced me even more to switch: bentonite is strip-mined from the earth, removing vegetation and layers of soil in the same way as coal mining. 

Obviously, the practice of removing limited clay reserves is not as sustainable as, for example, making litter from walnut shells, a waste product from the food industry, grown on trees and annually renewable. Strip-mining has a history of being environmentally destructive – land was stripped and then abandoned. These days, regulations are better (in some places, at least) – the top soil is spread back onto the land and planted with grass and trees when the miners move on. However, as Kapush (who runs a cat shelter in India and has many articles on cat litter) points out,  it’s still not ideal:

In general, however, reclamation can be very difficult. This is because the original ecosystem removed by the strip mine represents a delicate balance of plants, animals, microbes, and soil nutrients, and soil structure resulting from eons of plant succession and nutrient fluxes in and out of the system. Re-establishing this balance in the short-term is at best a scientifically challenging endeavor.

Walnut shells are shown next to Naturally Fresh brand of cat litter while a bentonite clay strip mine is shown next to Ever Clean litter.
Sometimes the best option is not that hard to see. You just need to visualize how the material is sourced. In this case, comparing cat litter made from walnut shells versus bentonite clay.

Other factors to consider

I would like to see Naturally Fresh (and other brands of plant-based litter) using cardboard instead of plastic packaging. Clorox do package their Ever Clean litter in a box that’s mostly made of recycled cardboard. However, this isn’t enough to outweigh the sustainability of the walnut-shell litter, in my opinion. On top of that, Clorox and the companies that make the other leading brands (Nestlé and Church & Dwight) do still conduct or contract animal testing.

It’s also worth considering corporate social responsibility in general: Clorox, although receiving various awards for CSR, did received a score of 0/100 from the Union of Concerned Scientists for their palm oil sourcing. Church & Dwight (Arm and Hammer brands) scores an F on Shop Ethical, dinged for poor environmental practices such as the use of microbeads. I’ve covered Nestlé (who make Purina brand litter) in previous posts on water and chocolate; personally I rank them as a company to avoid.  

How to dispose of cat litter

Some cities will accept cat litter in compost (green waste) bins, but San Francisco doesn’t – this is partly due to microbial contamination concerns. Cat poop may carry Toxoplasma gondii, a parasite responsible for killing marine life and flushing cat litter down the toilet is forbidden in California.

From what I’ve read, your plant-based cat litter (minus the poop) can be mixed in with your garden compost. If adding directly to your soil, it should be restricted to use on ornamental trees or flowers.


I found the Naturally Fresh walnut shell litter to be at least as good as the Ever Clean bentonite clay that it replaced. They both deserved a high gold star rating for functionality and price, but the walnut shell litter received a higher green star rating for social and environmental impact. How about you and your kitty – any recommendations?

20 thoughts on “Daily Footprint, #30 – Sustainable and Ethical Cat Litter

  1. Well done for covering this often ignored topic. With the rise of indoor kept cats the litter market is not to be sniffed at!;) I have a cat who spends her pennies outside, but when I have had to purchase litter I look for the woodchip based ones as they are sustainable, absorbent and compostable. However, the ethics of the company is another stumbling block, as you point out so well – I too avoid Nestle like the plague.
    Keep up the good work – and I hope your cat appreciates it 😉

    Liked by 3 people

  2. I buy Bob Martin traditional cat litter for my cat. I have kind of stuck with this brand because he is an elderly chap and I don’t want to make him grumpy 😦 by changing brands and types, although I accept there may be greener options out there. I have just Googled Bob Martin now and interestingly I can’t find anything that specifies what actually goes into their litter. I suspect it’s a clay though: small gravelly white granules. HOWEVER.. we do have an English walnut tree in our South African garden, so now you have me thinking to mix in a few crushed walnut shells with his usual litter. Maybe kitty would be cool with that.

    Liked by 1 person

    1. Haha. Yes, ultimately your cat may decide what is the most “sustainable” brand. Bob Martin (like pretty much all clay-based clumping litters) is made from bentonite. Yeah, you could try adding some crushed shells – lucky you, having a walnut tree!

      Liked by 1 person

  3. I had that for a while, and would have preferred using that walnut shells brand, but I have a little problem (ex-semi-feral) kitty, so I had to switch to World’s Best the lavender-scented one. I have a hilarious (though I wasn’t laughing at the time!), yet scary, story about World’s Best Litter. On a previous occasion with World’s Best litter, I had put fresh litter in after cleaning out the box. The next time I scooped poop, I was like “it’s moving”…I rub my eyes and look closer. Yep, the surface of the litter is rippling in waves. Thousands upon thousands of grain mites had exploded. They were over everything, books, radio, sheets, clothes, etc. It was horrible. There was no way to get rid of them but reduce the humidity (no mean trick in Florida) to below 50% and clean, clean, clean. Wipe and wash everything down, multiple times. Crazy! They did refund the money, but it took days to get rid of the infestation.

    Liked by 1 person

  4. It’s been many years since I was a cat owner, but I recall my favorite litter was Hartz pH5, mined from a naturally acidic clay, because it kept the ammonia (released from the decomposition of urea in urine) bound as a salt rather than smelly free ammonia gas.

    They don’t say on their website (they make 7 flavors) http://www.naturallyfreshlitter.com

    but this generic walnut shell product is pH 5.4: https://www.reade.com/products/walnut-shell-abrasive-media-grain-flour-powder

    Maybe jkaybay, being a scientist, can dip a pH meter into his sample 🙂

    Liked by 1 person

    1. Well, there’s no strong ammonia smell with the walnut shell litter. I thought it worked about as well as bentonite clay.
      Naturally Fresh is made by a company called Eco Shell (they also sell walnut shells for things like polishing, exfoliation, etc.) and according to their SDS the pH is between 4 and 6. http://www.ecoshell.com/sds.
      PS: I once knew a guy called D Luber 😉


  5. I have used walnut shell litter since Blue Buffalo first offered it in about 2012. It’s so natural for cats that mine didn’t need any introduction; they simply hopped in the litter boxes and used it. My cats love it and it doesn’t create dust. Also, it’s appropriate on my lawn when neighbors’ dogs leave a “little” diarrhea. Walnut shell litter doesn’t create slimy mud when wet, yet it absorbs both waste and odors. I’ve even been told to carry it in the winter for ice slicks in parking areas. I’m also told the Army has used ground walnut shells to clean turbines. It’s great that this is a natural, nontoxic agricultural by-product. A+++

    Liked by 1 person

    1. Yes! It’s so great to see what would otherwise be a waste by-product being put to good use. The shells are also used as natural exfoliants in scrubs – so much better than plastic microbeads! Thanks for taking the time to share your thoughts, Lorrie!


  6. Awesome story – walnut shell litter is the only litter on the market that actually works on odor control. It does not cover up or mask the orders it eliminates them. No perfume, carbon, fabreeze, baking soda! Just walnut shells that have been repurposed in the Ag cycle. I have used just about every litter on the market over the past years. Nothing better than Naturally Fresh

    Liked by 1 person

  7. It seems nearly impossible to find just the right cat litter. Dust, bugs, strip-mining… Do the walnut-based litters track much, in your experience? My two girls use World’s Best Multi-Cat, but one of them *always* tracks litter into my bed (bleahhhh), despite having to cross over a litter mat and a rug on her way. I’m in Florida, too, and so far I’ve been lucky enough not to have gotten a bag full of critters, but I feel like I’m living on borrowed time. Thanks for covering this subject!

    Liked by 1 person

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