The helmets are all made by the U.S. manufacturer ArmorSource, and the Army says there is a good chance that some of the faulty helmets were sent overseas to combat zones.
Army officials sent out a global recall notice Thursday night and announced the recall publicly late Friday.
The notice warned all Army troops to be on the lookout for advanced combat helmets made by ArmorSource.
An Army official tells ABC News that the recall notice says the following: there is evidence that the helmets "were produced using unauthorized manufacturing practices, defective materials and improper quality procedures."
The Justice Department has launched an investigation, but the agency will not discuss details of the case and neither will the Army.
ArmorSource released a statement today in response to ABC News, saying the company was "not informed of this recall" and that they "intend to request additional information and to cooperate in whatever inquiries the government might have."
So far there is no evidence that anyone has been injured because of the defective helmets.
The Army also says they have enough helmets in their inventory to replace the faulty ones, but first they have to determine exactly where the helmets are and who is using them.
Meanwhile, the Justice Department will tackle bigger questions about how so many faulty helmets were put into circulation in the first place.
The recalled helmets represent only 4 percent of the total helmets used by the Army, but military officials said they didn't want to take any chances.
Helmets can sometimes serve as a soldier's primary protection and compromising that in any way is something the Army wants very much to avoid.