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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.

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?

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