Lead Found in 99% of Cat Foods Tested as New Study Flags Heavy Metals in Popular Wet and Dry Pet Food Brands

A new study has found lead in nearly every cat food product it tested, along with widespread traces of other heavy metals, raising fresh questions for pet owners about what their cats eat every day.

The Clean Label Project, a nonprofit that tests and certifies consumer products, said it detected lead in 99 of 100 cat food products from 62 brands. The group also found cadmium in 96% of the products and arsenic in 94%.

The pet food industry pushed back, saying the findings lack the scientific and regulatory context needed to judge whether any products pose a risk.

"Because they are so common, the question is not whether a product contains heavy metals, but whether it contains relatively high or low levels compared with other products," the study said.

What the study tested

The Clean Label Project purchased 31 dry kibble products, 40 wet foods in cans and pouches, and 29 air-dried or freeze-dried products. Each was tested by an independent, accredited laboratory for more than 122 industrial and environmental contaminants and toxins.

To compare products fairly, researchers measured contaminants per 1,000 calories of food rather than by weight, since dry and wet foods contain very different amounts of water.

The group compared results against its own purity benchmarks rather than government safety limits. It said the study is designed to compare contaminant levels across products and does not determine whether any specific product will harm a cat.

Dry food higher in lead

Dry cat food contained about three times more lead than wet or air-dried food, according to the study.

The most contaminated products overall had more than three times as much lead as the least contaminated products.

No amount of lead is considered safe to consume. In humans, lead exposure is linked to damage to the brain, kidneys and nervous system. In pets, chronic exposure can contribute to similar problems over time.

Fish-based foods higher in mercury

The protein source in a cat food made the biggest difference in how products scored.

Nearly 85% of poultry-based foods met the Clean Label Project's standards, compared with just over a quarter of fish- and seafood-based products.

Fish and seafood products contained about 18 times more mercury than other foods, the group said. Nearly half of fish-based products ranked among those with the highest mercury levels, while no poultry-based products did.

Mercury builds up in fish through the food chain, particularly in larger predatory species such as tuna, a common ingredient in cat food.

Herbicides and plastics

The study also found contaminants beyond heavy metals.

The herbicide glyphosate appeared in 37% of products and was more common in cat foods containing plant ingredients. AMPA, a chemical created when glyphosate breaks down, appeared in 12% of products.

A plasticizer linked to hormone disruption was detected in 48 of the 100 products. Bisphenol A, or BPA, a chemical once common in can linings, was found in only two products, and a related chemical, BPS, in one, which the group attributed to a broader industry shift away from bisphenols in packaging.

Acrylamide, a chemical that can form when foods are cooked at high temperatures, was found at measurable levels in four products and at very low levels in 24 others.

Labels can mislead

The study also raised questions about ingredient labels. In 35 of the 100 foods, the meat or fish listed first on the label was not actually the main ingredient, according to the group, with plant ingredients making up most of the top 10 ingredients.

Why cats may be at greater risk

The Clean Label Project said cats may face greater exposure to contaminants than people because of how they eat.

"Most cats eat the same foods, or a small rotation of foods, every day for their entire lives," the study said. "Without any dietary variety, any contaminants present in the foods a cat eats can become a consistent and ongoing source of exposure, potentially accumulating in their bodies over the course of their lives."

Contaminant limits for pet food often rely on human health standards and general dietary assumptions, the group noted.

Industry disputes findings

The Pet Food Institute, which represents U.S. pet food makers, said the study's findings lack the scientific and regulatory context needed to interpret them, according to the trade publication Petfood Industry.

The institute noted that, as the Food and Drug Administration has said, whether a metal is harmful depends on several factors, including the level and duration of exposure.

A spokeswoman for the group also said the Clean Label Project's results "are based on a single batch of each product, limiting the conclusions that can be drawn from the results."

Heavy metals occur naturally in soil, water and air, and trace amounts are commonly found in many foods for both people and animals, including fruits, vegetables, grains and seafood.

The Clean Label Project has drawn criticism in the past from some consumer advocates who argue its certification labels can give shoppers a misleading impression that products are free of contaminants.

Advice for pet owners

The Clean Label Project recommended that cat owners:

• Rotate their cats' diets rather than feeding the same food every day.
• Choose wet or air-dried foods when possible to reduce lead exposure.
• Favor poultry-based foods over fish-based products to limit mercury.
• Limit foods that list plant ingredients near the top of the ingredient list.

The group also published lists of the dry and wet products with the lowest contaminant levels in its testing.

Veterinarians generally advise pet owners not to make abrupt changes to a cat's diet and to consult a veterinarian before switching foods, particularly for cats with health conditions or special dietary needs.

The FDA regulates pet food in the United States and requires that it be safe to eat, produced under sanitary conditions and free of harmful substances. The agency has not issued specific action levels for most heavy metals in pet food.