The Pentagon has recalled 44,000 advanced combat helmets, issued to its soldiers in the war zones of Afghanistan and Iraq, after an investigation revealed that these helmets do not meet the US army's specifications.
Investigations have been ordered into the matter.
Army officials, meanwhile, said these helmets - of substandard quality - do not pose a direct risk to soldiers.
The 44,000 recalled helmets represent about four per cent of the total number of Advanced Combat Helmets in the military's inventory, Army Brig Gen Peter Fuller said on Monday.
He said while the helmets failed to meet Army standards, there is no evidence that any soldier was ever harmed from their use.
The recalled helmets provided a safe degree of protection, Fuller said, but they were "just not up to our standards."
The Army, he said, is withdrawing the helmets from the field.
Fuller looks after development and testing of Army equipments. "Our number-one mission is to ensure every soldier's lethal survivability equipment can survive in any environment, and a helmet is a personal piece of equipment that provides that survivability."
"We want to make sure they never have any question as to whether or not this will be able to stop what it needs to stop," Fuller told reporters.
So far, none of the recalled helmets have been found at the Bagram Airfield Central Issue Facility, the main supply hub for troops deployed in Afghanistan, the officer added.