The effect of cat litter on the environment is several-fold, including the process of sourcing the materials for the litter, how it is disposed of, and its overall carbon footprint.
Firstly, we have to look at the composition of cat litter, which according to the American Chemical Society, is largely composed of bentonite, a type of mineral clay, which gives cat litter its clumping ability wherein it clumps together in the presence of moisture and traps the ammonia released from cat urine.
While there are newer kinds of cat litter, such as those made of silica gel, also known as “crystal” litter, the vast majority of cat litter is this clumping kind (75.6% market share).
As such, we’ll be looking at this kind as it’s the most popular but also potentially the most problematic.
1. How Does Cat Litter Affect the Environment?
According to a review of the cat litter industry in 2014, clay-based cat litter (as described above) is produced through a process that requires strip mining.
Strip mining, also known as surface mining, involves removing vegetation, soil, and rock layers to access mineral or coal deposits near the Earth’s surface.
However, it has significant environmental drawbacks. Strip mining destroys habitats, leading to biodiversity loss.
The removal of topsoil causes soil erosion and degradation, impairing fertility and increasing sedimentation in water bodies.
Moreover, water pollution occurs as exposed rock and soil release toxic substances, while runoff carries sediments and pollutants into rivers.
Strip mining also generates air pollution through dust, particulate matter, and the burning of extracted coal, which contributes to climate change.
Another impact of cat litter is also how it is disposed of, which is predominantly in the form of landfills.
For instance, the general US guidance on cat waste states that:
- it should be disposed of in the garbage
- it can’t be composted due to inherent bacteria
- generally, neither can it be disposed of down the toilet as the properties of bentonite can cause blockages.
This means that the vast majority of cat litter will end up in municipal waste, of which over 130 million tons end up in landfills.
Although we can’t see how much of this is actually a result of cat litter, a paper on the environmental footprint of domestic animals estimates that one cat generates approximately 0.24 tons of waste per year (1000 cats create 240 tons).
Since there are approximately 94.2 million pet cats in the US, that’s about 22 million tons of waste.
Not to mention the carbon footprint incurred by sourcing and depositing this litter from mining sites all the way through to disposal in landfill facilities.
The study highlights a total carbon footprint of 50 tons of carbon dioxide (CO2) per year (includes unused litter at 28.8 t, transportation of waste at 13.1 t, and actual waste at 8.1 t decomposition output).
To put this in perspective, it takes 50 trees to sequester just one ton of CO2, so to deal with 50t of CO2 in this way would require 2500 trees.
2. Is Cat Litter Toxic Waste?
In the US, for the most part, cat litter is not considered to be toxic waste (though, of course, there may be variances between state laws).
To note a few examples:
- In the State of New York – kitty litter is listed in Madison County as an item for garbage collection.
- In the State of Washington – domestic animals, non-livestock waste must be disposed of as solid waste.
- The State of California – also encourages the disposal of cat litter in the trash.
We would imagine these laws apply in most states as the EPA’s criteria for hazardous or toxic household waste does not include cat litter.
Assuming you don’t dispose of it in a way that could put others in harm, i.e., you do not accumulate it, and you put it into a garbage bag, it is household solid waste, which can go in the trash.
However, this does not mean that cat litter has no toxic risk. Bentonite, the main component of cat litter, is a composite of aluminum silicate and can contain crystalline silica.
While toxicological reviews highlight that bentonite itself is no more dangerous than any other airborne particulate, they still advise limiting exposure due to this potentiality.
Moreover, a study actually demonstrated that Sarcoidosis, an inflammatory autoimmune disease, may be linked to cat litter in some people, where it creates a hypersensitive reaction that mirrors “sarcoid-like” effects such as inflammation.
3. Is Cat Litter Biodegradable?
No, cat litter is not biodegradable.
For a product to be described as biodegradable, it needs to do two things:
- The item must be organic – that is, containing carbon.
- It can be broken down and decomposed naturally over time through the action of microorganisms, such as bacteria, fungi, or other biological agents, into simpler, non-toxic substances.
However, as bentonite (the main constituent of cat litter) is an inorganic substance (i.e., it does not contain carbon), it does not provide a source of nutrients for microbial metabolism.
As a result, microorganisms do not have the necessary enzymes or metabolic pathways to break down bentonite; thus, it can’t be biodegraded.
4. How to Dispose of Cat Litter in an Eco-Friendly Way?
When it comes to disposing of cat litter in an eco-friendly way, as we mentioned, for the most part, cat litter should be disposed of in the trash and not flushed down the toilet (due to blockage and contamination risk) or composted (since bacteria can’t break it down).
Unfortunately, recycling isn’t an option yet either, though in future this might be the case.
For instance, cat litter can be repurposed as an absorbent for hazardous spills, according to a publication by Utah State University.
They explain that small corrosive or toxic drips and spills can be absorbed using cat litter.
However, while cat litter can serve a secondary purpose for spill absorption or disposal, for the most part, many of us won’t have use for it.
For this reason, opting for biodegradable and eco-friendly cat litter is most likely to be the best option for reducing the environmental impact of cat waste disposal.
5. Are There Eco-Friendly Types of Cat Litter?
While non-biodegradable clay-based (bentonite) cat litter may dominate the market, that doesn’t mean that there aren’t more eco-friendly options available.
For instance, there is an increasing trend towards biodegradable cat litter, which replaces bentonite with renewable plant-based litter like wood, fruit parts, seeds, and plant residues (i.e., leftover stems, leaves, and roots).
There are also those which come from recycled materials, which can help cut down on production emissions like the carbon footprint we mentioned earlier.
World’s Best: This product comes from a global and US-based brand that creates silica-free, corn-derived cat litter.
It’s made to limit odor and allows easy clumping, with the added bonus of being biodegradable.
Ökocat: This cat litter is a Healthy Pet brand that derives its products from reclaimed wood. It is free from bentonite and silica, and it is naturally biodegradable.
The brand promises that its litter is odor free and 100% sustainably sourced. They are a German brand with offices and suppliers located in the US.
Naturally Fresh: This is a walnut-based, biodegradable cat litter brand. They claim their product is silica-free but still is naturally clumping to remove strong odors.
Moreover, they are based in the US, from their walnut farms to solar-powered shelling facilities.