The biggest concern of mine with more typical cat litter (clay/bentonite-based) is the level of lead as well as silica dust. I’m also concerned with wood dust in some types.
These three types are non-toxic for cats as well as the person cleaning the litter box.
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Potential Toxins found in kitty litter
Lead: Tamara Rubin has tested cat litter with an XRF analyzer. While most of the brands she tested did not have lead, she did find a brand with Lead (Pb) in the range of 27 +/- 11 ppm (equals 16 to 38 ppm) and one brand came in at 15 +/- 6 ppm Lead (source and source). This is a low level, but because it’s in dust form and being tracked around by kitty paws this could be a concern to cats and could possibly lead to toxicity says Dr. Mwuara. It’s also a concern for humans. Clay-based/bentonite-based kitty litter, or litter with a clay ingredient is the type that can have these low levels of lead (as all clay-based products can).
Silica: Crystalline silica is not safe for you or your cat, as breathing it in is harmful. The dust from crystalline silica can cause respiratory issues in cats, says Dr. Mwaura, and it has been linked to lung cancer and other health problems in humans (source). Amorphous silica gel is generally safe for your cat and for people to handle. Many clay-based cat litters (including bentonite clay) contain crystalline silica.
Wood dust: While the wood/bamboo/paper type litter products are usually labeled as low dust or 99% dust-free, breathing in wood dust is not safe for cats or humans. Wood dust can cause respiratory or allergic reactions in cats, says Dr. Mwaura. Wood dust is a Prop 65 Chemical known to the state of California to cause cancer in humans (Proposition 65).
Fragrance: Some cats don’t do well with scented litter which can trigger allergic reactions and/or respiratory problems in cats, Says Dr. Mwaura. Many humans are also sensitive to fragrance chemicals, if you are a regular reader of my site then fragrance in cat litter is probably not for you.
Recycled Tires: While this type looks like it might have been discontinued, recycled tires contain many contaminants of concern that are outlined in my article on gym flooring. Old tires release compounds including VOCs, polyaromatic hydrocarbons, and toxic metals.
1. World’s Best Cat Litter
World’s Best Car Litter is corn-based. It’s made of whole-kernel corn grown in the US. Real users say it does a great job of clumping and produces very little dust, but it doesn’t control odor as well as clay-based litter does. Reviewers did also report some tracking.
This brand is 99% dust-free, free of silica dust, and free of harmful metals. It tested positive for low levels of Bromine (Br): 4 +/- 1 ppm, Zinc (Zn): 27 +/- 5 ppm and Iron (Fe): 62 +/- 13 ppm. It tested non-detect/negative for all harmful metals, including: Lead (Pb), Arsenic (As), Cadmium (Cd), Mercury (Hg), Barium (Ba), Selenium (Se), and Antimony (Sb) (source).
I would recommend going with the unscented, because added fragrance is not always safe for everyone.
The pros: it’s biodegradable, made from a renewable resource, low dust, flushable, safe for septic and sewer systems.
The cons: some cats (and humans) may be allergic to corn, not as good at odor control compared to other types, more expensive than clay-based litter.
2. Dr. Elsey’s Respiratory Relief Gel Cat Litter
“Crystal” or amorphous silica cat litter is non-toxic and completely safe for cats and humans. Dr. Elsey’s Respiratory Relief Gel Cat Litter is a well-liked brand.
Crystal cat litter is composed of amorphous silica gel granules (this is very different from crystalline silica, which is harmful to breathe in). It’s absorbent and lightweight. Liquid and odors are trapped. It’s as low dust as you can get. It does track somewhat like all litter materials do, but putting a mat outside the litter box does help.
The pros: it’s non-toxic, very absorbent, long-lasting, has good odor control, is easy to clean, is low dust compared to clay, and is lightweight, good for many cats that have allergies or respiratory problems.
The cons: has to be mined (harder on the environment than a recycled product or one made from waste materials), not biodegradable, tracks easily, more expensive than other types, some cats may not like the texture, can get dusty.
3. sWheat Scoop Original
Made from 100% natural wheat grown in the US, sWheat Scoop Original clumps fast, scoops easily, and smells like a fresh wheat harvest.
They say it is virtually dust-free (99.5% dust-free, though reviewers did notice some dust), and tracking is minimal (though some reviewers didn’t find the tracking to be low). They have an option that is intended for only one cat as well as a multi-cat option.
It has odor-neutralizing enzymes and clumps well. I would recommend the unscented version.
The pros: flushable, 100% biodegradable, renewable resource, low dust, good odor control, good clumping ability.
The cons: possible allergy to wheat (humans or cats), not as absorbent as other types, more tracking the other types, could attract insects when left too long, more expensive than clay-based litter.
World’s Best | Dr. Elsey Gel | sWheat | |
Type | Corn | Amorphous silica | Wheat |
Dust | 99% dust free | 99.9% dust free | 99.5% dust free |
Odor Control | Mediocre | Great | Good |
Tracking | Yes | Yes | Yes |
Clumping | Great | Doesn’t clump in the same way but still works well | Great |
Cost* | Around $1.15 per pound | Around $2.70 per pound | Around $1.10 per pound |
Corinne Segura holds certificates in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes.
Miriam
My cats like the Naturally Fresh (recycled walnut hulls). Clumps well.. tracking is easy to sweep up . Minimal dust
Starr Adams
Hi Sarah, I would be concerned about residual glyphosate in the corn and wheat-based products since the majority of those crops are sprayed with it.
Sarah
Also, if you have a finicky cat (is there any other kind?!) and they will only use a litter that produces dust, don’t use a littler box w/a lid since it holds the dust inside forcing them to breathe more of it in.