A cereal study conducted this year discovered that the active ingredient in Monsanto’s weed killer Roundup is still in Cheerios and other cereals.

There are 21 oat-based cereal and snack products that tested positive for traces of glyphosate, the aforementioned active ingredient in these products. The chemical is found in Roundup, which has led to a number of trials that claim the weedkiller causes cancer in the people who consume it.

The study was conducted by the Environmental Working Group (EWG), which said that the tests found glyphosate levels that were above what it considers to be safe for children in all but four of the products it tested. The 21 products that it tested were all made by General Mills (NYSE:GIS), which includes six varieties of Cheerios, as well as 14 of General Mills’ Nature Valley products, including Nature Valley granola bars.

General Mills responded by saying that food safety is a “top priority” for the company, which said it is making an active effort to reduce the use of pesticides on the ingredients it uses. “Most crops grown in fields use some form of pesticides and trace amounts are found in the majority of food we all eat,” the company said in an emailed statement.

“Experts at the FDA and EPA determine the safe levels for food products,” which the company says it adheres to–the farmers that grow these crops do too, the business said.