What’s Really in Your Cat’s Food?
A toxicologist’s read on the new heavy metal and contaminant study
A new report found lead, cadmium and arsenic in nearly every cat food it tested. But finding a contaminant is not the same as finding a harmful dose, and that distinction is the whole story.
If you’ve seen the headlines and looked at your cat’s bowl with a little dread, that reaction makes sense. Words like “lead” and “arsenic” are alarming, and pet owners deserve straight answers. My training is in toxicology and animal nutrition, and I formulate commercial pet foods for a living, so let’s walk through what this study actually measured, what it can and can’t tell us, and how to choose a food you feel good about.
The short version
- Trace heavy metals were detected in almost every product, which is expected with modern lab sensitivity. The report does not compare results to safety limits.
- The useful signals are patterns: fish-based foods carried more mercury and cadmium, and dry foods carried more lead.
- The best response is calm: feed a complete and balanced diet, rotate proteins, go easy on daily tuna, and choose brands that test.
What the study did and found
On October 2, 2026, the US nonprofit Clean Label Project released its Cat Food Category Report, testing 100 top-selling cat foods from 62 brands for more than 122 contaminants. Products were bought at retail in three formats: dry, wet, and air-dried or freeze-dried. Testing was done by an ISO 17025-accredited laboratory, and the work follows the group’s dog food report from earlier this year, which I covered in my deep dive on heavy metals in dog food.
| Finding | Result |
|---|---|
| How often contaminants were detected | |
| Lead | 99% of products |
| Cadmium | 96% of products |
| Arsenic | 94% of products |
| DEHP, a plasticizer | About 50% of products |
| Glyphosate, an herbicide | 37% of products |
| How products compared | |
| Mercury in fish and seafood foods vs other proteins | About 18x higher |
| Lead in dry foods vs wet or air-dried | About 3x higher |
| Met the group’s own purity standard | 85% poultry, 25.7% fish |
Source: Clean Label Project press release, October 2, 2026.
One thing the study did well: because wet and dry foods differ so much in water and energy, results were standardized per 1,000 kcal. That reflects what a cat actually eats to meet its energy needs, not the weight of food in the bowl. If that concept is new to you, my guide to as-fed versus dry matter and the as-fed to 1,000 kcal calculator explain how it works.
The toxicologist’s read: detection is not dose
The first principle of toxicology is that the dose makes the poison. Modern instruments can measure metals in the parts-per-billion range, so finding trace lead in 99% of foods made from animal tissue, minerals and crops grown in soil is expected. The meaningful question is how much, compared to what threshold, and that is the part this report does not answer.
Here are five things I’d want every reader to keep in mind.
Select each point to expand it.
The “purity standard” is Clean Label Project’s own scoring system, not a safety limit. Results were not presented against established references such as the National Research Council’s maximum tolerable levels for cats or the EU’s legal maximums for pet food. A food can rank poorly on a purity score and still sit comfortably below any level linked to harm.
“18 times more mercury” is striking, but 18 times a very small number can still be a small number. Without absolute concentrations and an exposure estimate per kilogram of body weight, a ratio tells you which direction to look, not whether there is a problem.
Most of the arsenic in fish is arsenobetaine, an organic form that is poorly absorbed and passed through largely unchanged. Mercury in fish, by contrast, is mostly methylmercury, which does matter. A total-element test can’t tell those forms apart, so total arsenic tends to overstate risk in seafood diets.
Each product was tested from a single lot. Ingredient lots vary with season, region and supplier, so one result can’t characterize a product, and it can’t be used to rank brands with confidence.
Chronic kidney disease is common in older cats, and the kidneys do handle metals like cadmium. But feline kidney disease has many contributors, and this study did not examine any cats. It is a reasonable question for future research, not a conclusion. If your cat already has kidney concerns, my guide to the best cat food for renal support is a better place to focus.
To be fair to the study
Retail sampling, an accredited lab, independence from brands and per-kcal standardization are all good practice. My critique is about interpretation, not that the data are worthless.
Where these contaminants come from
None of these substances are added on purpose. They ride in on ingredients, equipment and packaging. Knowing the route explains the patterns, and the patterns are the most useful part of this report.
Choose a contaminant to see how it enters pet food and what the study found.
How it gets in
Builds up through the marine food chain, so it is highest in large, long-lived predatory fish such as tuna.
What the study saw
About 18 times higher in fish and seafood foods, and about 28 times higher in wet fish foods than other wet foods.
How it gets in
Taken up from soil by crops, and concentrated in marine organisms and organ tissues.
What the study saw
Detected in 96% of products, and about 2.5 times higher in fish and seafood foods.
How it gets in
Environmental deposition in soil, bone content, some mineral sources and wear from processing equipment.
What the study saw
Detected in 99% of products, and about 3 times higher in dry foods per 1,000 kcal.
How it gets in
Naturally present in marine foods, mostly in low-toxicity organic forms, as well as in soil and water.
What the study saw
Detected in 94% of products. The report measured total arsenic, not the form.
How it gets in
Residue on conventionally grown crops treated with the herbicide.
What the study saw
Detected in 37% of products, with higher levels where crop ingredients sat near the top of the ingredient list.
How it gets in
Contact with PVC tubing, gaskets and some can or pouch materials during processing.
What the study saw
Detected in about half of products, and about 5 times higher in canned and pouched foods than bagged foods.
The seafood signal is the clearest and most actionable finding. Cats are famously drawn to fish, and many owners feed tuna-based foods daily. Rotating in non-fish proteins is a simple way to lower mercury exposure without giving anything up nutritionally. I covered this in more depth in should cats eat fish every day?
The dry food lead result deserves follow-up rather than alarm. Likely contributors include bone content in rendered protein meals, mineral sources and processing, but the report doesn’t break this down. If you’re curious about those steps, here’s how kibble is made.
No single protein or format is clean on every measure. Chicken-based foods were better for mercury and cadmium but showed more lead and herbicide.
The nutritionist’s read: don’t trade a hypothetical risk for a real one
The biggest danger after a report like this is overcorrection. Nutritional deficiencies are a proven, well-documented cause of illness in cats, while harm from trace contaminants at these levels has not been shown. A reaction that makes the diet less complete is a step backward.
If you’re thinking about
Switching to homemade
Published homemade cat recipes are often short on essentials like taurine, calcium, vitamin E and choline. Home ingredients contain trace metals too, they just aren’t tested. If homemade appeals to you, work with a qualified pet nutritionist so the recipe is complete.
If you’re thinking about
Cutting out fish entirely
Fish and fish oil supply EPA and DHA, the omega-3s that support skin, joints, kidneys and cognition. Refined fish oils are typically purified and very low in mercury. See my guide to the best omega-3 sources for cats.
If you’re thinking about
Dropping wet food because of DEHP
Cats have a low thirst drive, and wet food supports hydration and urinary health, a benefit that is well established. Mixing formats is a better answer. More on that in wet vs dry food for cats.
If you’re thinking about
Judging a food by its first ingredient
A well-formulated food is defined by its nutrient profile, digestibility and the quality control behind it. The ingredient list shows what went in, not whether the diet is balanced. Here’s how marketing shapes what we notice.
Variety is the quiet hero here
Rotating between two or three complete and balanced foods with different proteins and formats spreads exposure across different supply chains, so no single source dominates your cat’s diet for years. Use the cat daily calorie calculator to keep portions right when you mix foods.
The regulatory gap is the real story
The most legitimate concern this report raises is not the numbers themselves but how little formal oversight exists for them in North America. Standards vary sharply by region.
European Union
Legal limitsLegal maximum levels for lead, cadmium, mercury and arsenic in complete pet foods, set under EU feed law.
United States
Guidance onlyNo federal limits specific to pet food. The FDA can act against adulterated products, and industry generally references National Research Council tolerance guidance. Read more on what AAFCO approval really means.
Canada
Largely voluntaryNo federal composition standards for pet food. Oversight relies on industry codes and each manufacturer’s own food safety program.
That means in Canada and the US, contaminant control depends heavily on each manufacturer’s supplier specifications, testing and quality systems. Many responsible companies do this well. The problem is that consumers usually can’t see it, which is exactly why reports like this one get traction. Food safety oversight has gaps elsewhere too, as I discussed in H5N1 as a pet food safety hazard.
The Pet Food Institute’s response, that contaminant studies need context on sampling, methods and safety thresholds, is scientifically fair. It would be even more persuasive alongside a push for clear, published limits, so that both brands and owners have a benchmark to point to.
How to choose a quality, clean cat food
The best protection is a complete and balanced food from a manufacturer that can show you how it controls contaminants. Here is the approach I recommend to clients.
Start with the nutrition fundamentals
- Confirm the food is complete and balanced for your cat’s life stage, meeting AAFCO nutrient profiles or the European FEDIAF guidelines. This should be stated on the label.
- Prefer brands that employ or consult a qualified animal nutritionist and can tell you who formulates their diets.
- Make sure the brand can share a full nutrient profile, ideally per 1,000 kcal, not just the guaranteed analysis.
Then ask the manufacturer about contaminant control
Use this as a checklist when you contact your cat’s food brand. Tick each question they answer clearly.
0 of 6 answered clearly
A few habits at home
Rotate proteins and formats
Two or three complete foods with different main proteins spreads exposure across supply chains.
Treat tuna as one option
Rotating fish foods with poultry, rabbit or other meats is the most effective way to lower mercury.
Keep wet food in the mix
Store leftovers in glass or stainless steel rather than in the open can.
Read purity rankings with care
A single-batch score is not a safety rating. Here’s what clean label really means.
The bottom line
This report shows that trace contaminants are common across cat food, and that protein source and format shape which ones show up. It does not show that cat food is unsafe, and it can’t tell you whether your cat’s specific food is a problem.
The practical response is calm and simple: feed a complete and balanced diet, rotate proteins and formats, go easy on daily tuna, keep moisture in the diet, and choose brands willing to tell you how they test.
Not sure how your cat’s food measures up?
I’m a companion animal nutritionist with a background in toxicology. I can review your cat’s current diet, explain what the label and nutrient profile really say, and help you build a rotation you feel confident about.
Keep reading
Sources
- Clean Label Project, Cat Food Category Report, October 2026.
- Clean Label Project, press release on the cat food study, October 2, 2026.
- Eastern Eye, Nearly all tested cat foods contained traces of heavy metals and other contaminants, study finds, October 2, 2026.