Almond milk is a great alternative to regular dairy milk. It can have just as much flavor, but it’s free of lactose and has lower calories. What it shouldn’t have, however, is actual dairy milk, which is why one company is doing a mass recall of its brand of almond milk.

HP Hood LLC, maker of the Blue Diamond Vanilla Almond Breeze almond milk recalled 145,254 half-gallon cartons on Thursday due to the addition of milk according to the U.S. Food and Drug Administration. The company’s volunteer recall stems from the facts that milk is an allergen that can cause some discomfort when consuming it, but it is safe to drink otherwise.

The states affected by the recall are Alabama, Arkansas, Connecticut, Florida, Georgia, Iowa, Illinois, Indiana, Kentucky, Louisiana, Maryland, Maine, Minnesota, Michigan, Missouri, Mississippi, North Carolina, Nebraska, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, and Wisconsin. Cartons with the additional milk will have a use-by date of September 2, 2018.

Those who purchased the affected almond milk can return the product to the store where it was purchased or contact Blue Diamond for a return. So far, one case reported an allergic reaction, but medical treatment was not needed.

As of yet, there is no explanation for how dairy milk found its way into the almond milk. This incident does raise some questions considering the two kinds of milk have very different productions processes or it could be a simple mistake of mixing them together at one plant.

Almond milk is a controversial point over at the FDA in recent weeks. The agency’s commissioner commented on how “an almond doesn’t lactate” in July due to the recent fight over the definition of “milk” and whether the almond and other non-animal versions can carry that name along with the original dairy milk.