General Mills said Monday it is recalling 1.8 million boxes of Cheerios and Honey Nut Cheerios after wheat flour contaminated its gluten-free production system at plant in California.
The boxes affected were made at the company’s facility in Lodi, Calif., in July, according to CNBC. The company said that the products could have “potential adverse health effects” for those who have celiac disease, or are allergic to wheat.
“Cheerios and Honey Nut Cheerios produced on these dates at the company’s Lodi, California facility are being recalled because an isolated incident resulted in wheat flour being inadvertently introduced into the gluten free oat flour system at its Lodi facility,” the company said in a recall announcement. “As a result, the products may contain an undeclared allergen—wheat—in products labeled as gluten-free.”
General Mills said that no other cereals it produces were affected because of the incident.
The brand took to Twitter to post the cereals included in the recall:
For more on General Mills, read this Fortune story on the company’s plan to go green.