(Luke Sharrett/Bloomberg)

General Mills is voluntarily recalling about 1.8 million boxes of gluten-free original and Honey Nut Cheerios because of the possible presence of wheat, the company announced Monday.

Jim Murphy, senior vice president of the company's cereal division, said he was "embarrassed and truly sorry" by an incident that allowed wheat flour to get introduced into the gluten-free oat flour system at a production facility in Lodi, Calif.

The "undeclared allergen" could cause adverse health effects for those with wheat allergies, celiac disease or gluten intolerance -- people who shouldn't consume affected products, the company said in a statement.

Affected boxes of original Cheerios were produced over four days in July, and affected Honey Nut Cheerios were produced over 13 days, according to the company. (See affected boxes' "Better if used by" dates below). About 150,000 cases shipped nationally fall under the recall, a spokeswoman said.

The company said it will remove affected boxes from store shelves and warehouses, and costumers with affected products can contact General Mills for a replacement or refund.

"Our Lodi production facility lost rail service for a time and our gluten-free oat flour was being off-loaded from rail cars to trucks for delivery to our facility on the dates in question," Murphy said. "In an isolated incident involving purely human error, wheat flour was inadvertently introduced into our gluten-free oat flour system at Lodi."

As the Wall Street Journal notes, "U.S. consumers have started to shun gluten, which is found in wheat and other widely used grains. Some 20 million Americans have either a sensitivity to gluten or a hereditary condition called celiac disease in which ingesting gluten damages the small intestine. But others have turned to a gluten-free diet in hopes of losing weight or gaining other health benefits."

To cater to the gluten-free market, General Mills announced in February that it would transition its facilities so that five varieties of Cheerios would be gluten-free. According to the company, products produced at the Lodi plant on other dates are safe for those with gluten allergies to consume.

Multiple people posting on the Celiac Disease Foundation's Facebook page said they had loved ones who consumed some of the affected Cheerios products.

"My son is 4 and has celiac," one person wrote. "His allergy is very serious. He has ate cheerios for the last couple weeks. Hes been sick off and on for 2 weeks. We have tried to think of anything that could be causing it and blamed it on the school.

"Last night he got really sick with a severe allergic reaction and spent the night in the ER and all day today at his pediatricians office. He is miserable. Came home and checked the box we have open right now and sure enough, its the same code. We have been thru quite a few boxes in the last couple weeks as I also have 2 teenagers that eat cereal for every meal and snack I will let them. My heart is broken as I watch our little guy suffer."

Wrote another: "My celiac daughter had them and this could explain why she has been sick the past days. We had finished the box so I no longer have it around. At least I have a reason why she was sick but I have to say my wife told me not to give her theses Cheerios to begin with even if they claim to be Gluten Free... #fail."

Said Murphy, the General Mills executive: "We sincerely apologize to the gluten-free community and to anyone who may have been impacted."

"Better if used by" dates for recalled Honey Nut Cheerios:

12JUL2016LD
13JUL2016LD
14JUL2016LD
15JUL2016LD
16JUL2016LD
17JUL2016LD
18JUL2016LD
20JUL2016LD
21JUL2016LD
22JUL2016LD
23JUL2016LD
24JUL2016LD
25JUL2016LD

"Better if used by" dates for recalled original Cheerios

14JUL2016LD
15JUL2016LD
16JUL2016LD
17JUL2016LD

This post, originally published on Oct. 5, has been updated.

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