The fun, colorful packaging aimed at kids and the ease of use for parents make it hard to accept that Lunchables actually contain harmful heavy metals and chemicals that could have negative health effects.

A study by Consumer Reports this week found that several versions of Lunchables and generic look-alikes contained lead and cadmium, which have been linked to health problems in both children and adults. Of the 12 store-bought Lunchables and Lunchable-style products the nonprofit tested, every single one contained either one or both of the heavy metals. Although none of the products ran afoul of the law with the levels of heavy metals, experts say that even low doses of lead and cadmium can affect child development and have been linked to increased risk of hypertension, kidney damage, and other health issues in adults.

While there is no national standard limit on the amount of heavy metals that can be found in most foods, Consumer Reports measured lead levels as a percentage of the California maximum allowable dose level (MADL)—the most rigorous in the country.

Lunchables maker the Kraft Heinz Co. told Consumer Reports that its products “meet strict safety standards” and added that “lead and cadmium occur naturally in the environment and may be present in low levels in food products.” The company did not immediately respond to Fortune’s requests for comment.

Although lead and cadmium are naturally found in the environment, the researchers conducting Consumer Reports’ study said that the levels of lead found in the products it tested were relatively high for its small serving sizes.

The highest lead levels were found in Lunchables Turkey & Cheddar Cracker Stackers, which contained 74% of the maximum allowable dose level for lead in California. That product was followed closely by Lunchables Pizza With Pepperoni, which contained 73% of the allowable level for lead. In total, five of the 12 products tested by Consumer Reports contained more than 50% of the maximum allowable dose level for lead. Apart from those made by Kraft Heinz, the products with more than 50% of the maximum allowable dose level for lead were Smithfield’s Armour LunchMakers and Target’s Good & Gather brand.

Smithfield Foods said in a statement to Fortune that it follows “strict programs and policies that promote food safety and quality in every step of our value chain.” A spokesperson for Target told Fortune in a statement, “We require our products to comply with all applicable federal, state, and local requirements.”

Although the Kraft Heinz Co. doesn’t break out sales for Lunchables specifically, “real food snacking,” the business category it shares with products like nuts, seeds, and trail mix, brought in $1.2 billion in net sales for the company in 2023. That’s about 4.7% of the company’s total net sales of just over $26.6 billion for its most recent fiscal year.