The Minnesota based company, 3M, contracted with the US government to provide the military with earplugs to help prevent hearing loss in soldiers during combat and training.

The earplugs sold by 3M were defective because they didn’t maintain a tight seal and allowed dangerously loud sounds to slip through.

The defective 3M earplugs resulted in hearing loss, tinnitus (ringing in the ears), and loss of balance in those who used 3M’s dual-ended Combat Arms earplugs during their military service between 2003 and 2015.