(The Hill) — The popular kids snack Lunchables contains relatively high levels of lead and sodium, a consumer watchdog group warned Tuesday.

Consumer Reports, a consumer advocacy group, said it tested 12 store-bought versions of Lunchables — which are made by Kraft Heinz — along with similar lunch and snack kits and found “relatively high levels of lead and cadmium” in the Lunchables kits.

Cadmium is a chemical element linked to negative effects on the kidney and the skeletal and respiratory systems and is classified as a human carcinogen, according to the World Health Organization.

There is not a safe level of lead for children, the Centers for Disease Control and Prevention notes.

The sodium levels in the kits ranged from 460 to 740 milligrams per serving, nearly a quarter to half of a child’s daily recommended limit for sodium, Consumer Reports said.

All but one of the kits contained harmful phthalates — chemicals found in plastic that can be linked to reproductive issues, diabetes and some cancers.

When testing the Lunchables kits distributed by schools under the National School Lunch Program, Consumer Reports found the sodium levels in these kits, which have larger portions of meat, are higher than the store-bought versions. The school version of the turkey and cheddar lunch had 930 milligrams of sodium, while the Lunchables pizza kit for schools had 700 milligrams of sodium.

A spokesperson for Kraft Heinz said Lunchables products provide a “good source of protein” and offer nutrients through meat and cheeses.

“We’ve taken great steps to improve the nutrition profile of Lunchables,” the spokesperson said, pointing to the reduction of sodium in the crackers by 26%.

“All our foods meet strict safety standards that we happily feed to our own families. We are proud of Lunchables and stand by the quality and integrity that goes into making them,” the spokesperson added.

Consumer Reports started a petition calling on the United States Department of Agriculture (USDA) to remove the Lunchables food kits from the National School Lunch Program. The petition had more than 12,000 signatures as of Tuesday night.

“Lunchables are not a healthy option for kids and shouldn’t be allowed on the menu as part of the National School Lunch Program,” said Brian Ronholm, director of food policy at Consumer Reports.

A USDA spokesperson said the agency takes their responsibility “very seriously” in ensuring “school meals are of the highest nutritional quality.”

“Importantly, USDA doesn’t allow or disallow individual food items. Our requirements address the overall content of meals — some of them on a daily basis and others on a weekly basis,” the spokesperson said to NewsNation partner The Hill.

The Lunchables products referenced by Consumer Reports would need to be paired with fruit, vegetables and milk, the USDA spokesperson argued. They noted a school serving a higher sodium product one day is expected to balance that with lower sodium items on others and said the agency is supporting schools looking to use more scratch-cooked and local foods.

The Hill’s Sarah Fortinsky contributed reporting.