If you recently purchased a box of “gluten-free” Cheerios, it may not actually be gluten-free.

General Mills is “embarrassed and sorry” to have to recall approximately 1.8 million boxes of Cheerios and Honey Nut Cheerios.

The Cheerios recall amount to several days of production, and is due to an “undeclared allergen – wheat”. General Mills says that some boxes marked “gluten-free” may, in fact, contain wheat after a flour mix-up.

“Cheerios and Honey Nut Cheerios produced on [certain dates in July] 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. As a result, the products may contain an undeclared allergen – wheat – in products labeled as gluten-free,” says the company.

“We want to reassure you that this was an isolated incident and we have implemented a solution to ensure that this will not happen again. The Cheerios and Honey Nut Cheerios produced at our other facilities are, and will continue to be, FDA compliant and gluten-free. We’ll also continue to test products and our oat flour supply extensively to ensure our products meet the gluten-free standard. We care about what you and your family eat and we are truly sorry for this mistake. We will work extremely hard to earn back your trust.”

Check this graphic to find out if the box of Cheerios sitting in your pantry is affected:

This recall only affects products sold in the US, not those distributed by General Mills Canada.

The Food and Drug Administration says it received 125 complaints about the Cheerios before the voluntary recall.