Thousands of UK veterans and serving military personnel are now bringing a separate legal case against 3M for supplying what they say were faulty ear protectors between 2003 and at least 2015, when they were replaced by a new model.
Its combat arms earplugs (version 2) were designed to be reversible, with one side blocking out most sounds, and the other protecting against impact sounds such as explosions while letting in spoken commands and other quieter noises.
In 2018 the company paid $9.1m (£6.8m) to settle a lawsuit brought by the US Department of Justice which alleged the company knew the earplugs were too short and could "loosen imperceptibly".
Five years later, in August 2023, it agreed to a $6bn (£4.5bn) settlement to resolve 240,000 civil cases being brought by US military veterans and those still serving.
Around $2.75bn (£2bn) has been paid out to date, according to the Lawsuit Information Centre, but 3M has never accepted legal liability, arguing that its products were always "safe and effective" if used correctly.
This week the first formal legal claim was launched in the UK with a "letter before action" sent to 3M on behalf of more than 2,000 veterans and current military personnel.
"As yet, there's been no justice and no compensation for British servicemen and women," says Tom Longstaff, a partner at KP Law, which is bringing the case.
"We've got very strong evidence that this product was defective, [and] that it suffered from a design flaw, which is well-documented in some of the cases that have already proceeded in the US."
A spokesman for 3M said the company had "great respect" for the British Armed Forces and it took the allegations concerning the product seriously.
"The resolution of previous litigation in the US did not involve any admission of liability and 3M is prepared to defend itself in any litigation threatened in the English courts," he said.