Study Finds Heavy Metals, Plastics and Herbicide Residues in Most Cat Foods Tested in U.S.

A new study by the U.S.-based nonprofit Clean Label Project has found that nearly all cat food products tested contained contaminants, including plastic-related chemicals, the herbicide glyphosate, and heavy metals such as lead, mercury, arsenic and cadmium.

The researchers analyzed 100 popular cat food products from 62 brands, screening them for more than 122 potential contaminants. The findings showed that 99% of the products contained lead, 96% contained cadmium, and 94% contained arsenic. The contaminants were detected across all product types, including wet, dry and frozen cat food.

Molly Hamilton, executive director of the Clean Label Project and lead author of the study, said the findings are particularly concerning because most cats consume the same food every day, increasing the possibility of long-term exposure to contaminants.

"Heavy metals are of particular concern because cats become more susceptible to chronic kidney disease as they age, and the kidneys play a critical role in eliminating these toxins from the body," Hamilton said.

The study found that dry cat food contained nearly three times more lead than wet or frozen varieties. Fish- and seafood-based products also recorded significantly higher levels of mercury and cadmium compared with foods made from other animal proteins.

According to the analysis, fish- and seafood-based cat foods contained approximately 18 times more mercury and 2.5 times more cadmium than products made with other protein sources.

Chicken-based formulas performed relatively better in terms of mercury and cadmium contamination but showed higher levels of lead and glyphosate.

Researchers detected glyphosate, a widely used herbicide, in 37% of the products tested. They also found that glyphosate concentrations increased with the number of plant-based ingredients listed among the first 10 ingredients on the product label.

Cat foods containing two plant-based ingredients had roughly 40% higher glyphosate levels than those with only one such ingredient, while products containing five plant-based ingredients recorded nearly four times higher levels.

The study also identified DEHP, a type of phthalate commonly used in PVC plastics and certain food-processing materials, in nearly half of the samples. DEHP was found more frequently in canned and pouch-packaged cat foods, suggesting that contamination may occur during food processing through contact with PVC pipes or other manufacturing equipment.

The researchers acknowledged several limitations in the study. Only one batch of each product was tested, meaning contamination levels may vary between production batches. The study also did not determine whether any specific product posed a direct health risk to cats.

The authors advised pet owners not to judge a product's safety solely by its ingredient list. They noted that labels often do not specify which parts of fish are used in the food, making it difficult to assess contamination risks. Instead, they recommended choosing manufacturers that routinely test their products for contaminants and maintain transparent quality-control practices.