3M Combat Arms Earplugs Litigation — Largest MDL in U.S. History

The 3M Combat Arms Earplugs litigation was unprecedented in scale. With over 300,000 individual claims, it was the largest MDL in United States history — dwarfing even the Roundup and talcum powder litigations combined.

3M's Combat Arms Earplugs Version 2 (CAEv2) were standard-issue hearing protection for U.S. military personnel from 2003 to 2015. The dual-ended earplugs were designed to provide two levels of protection: one end for steady-state noise (like engine noise) and the other for impulse noise (like weapons fire). The device was supplied to every branch of the military and used in training and combat zones including Iraq and Afghanistan.

The litigation's origins trace to a 2018 False Claims Act whistleblower lawsuit, in which 3M paid $9.1 million (without admitting liability) to resolve allegations that the company knowingly sold defective earplugs to the military. The whistleblower alleged that the earplugs were too short for proper insertion into the ear canal and that the flanged design could cause them to loosen imperceptibly, reducing the noise reduction rating below safe levels.

Internal Aearo Technologies documents (3M acquired Aearo in 2008) produced during litigation showed that the company was aware of design flaws during pre-sale testing — specifically that the earplugs did not fit properly in many users' ears — but manipulated testing protocols to achieve favorable noise reduction ratings for the military contract.

Noise-induced hearing loss (NIHL) is the most common service-connected disability among U.S. military veterans, affecting an estimated 2.7 million veterans. Military personnel are routinely exposed to noise levels exceeding 140 decibels from weapons fire, explosions, aircraft, and heavy equipment — levels that can cause immediate and permanent damage to the delicate stereocilia (hair cells) of the inner ear's cochlea.

The CAEv2 earplugs' alleged design flaw — insufficient stem length causing the earplug to loosen imperceptibly in the ear canal — meant that the actual noise reduction experienced by users was significantly less than the rated protection. Even small reductions in earplug effectiveness can be catastrophic at military noise levels, where the difference between adequate and inadequate protection determines whether permanent hearing damage occurs.

Tinnitus — persistent ringing, buzzing, or hissing in the ears — affects millions of veterans and can be profoundly debilitating, causing sleep disruption, difficulty concentrating, anxiety, and depression.

This litigation has been substantially resolved through the $6 billion settlement. Eligible claimants include U.S. military service members and veterans who used 3M Combat Arms Earplugs (CAEv2) during military service between 2003 and 2015 and subsequently developed hearing loss or tinnitus. Claims are being processed through the settlement program.

This eligibility information is general and informational only. Consult a licensed attorney.

RESOLVED — 3M agreed to pay $6 billion in August 2023 to resolve the vast majority of claims — one of the largest mass tort settlements in history. The settlement is structured as payments over several years, with distributions underway as of 2026.

Claims administration is processing individual payments based on the severity of hearing loss and tinnitus documented in VA medical records and audiological evaluations. Some cases remain pending, and 3M attempted to use its subsidiary Aearo Technologies' bankruptcy to limit liability, but the bankruptcy court rejected this approach.

16 bellwether trials were conducted before the settlement, with mixed results — plaintiffs won 10 and defendants won 6.

3M argued that the CAEv2 earplugs were safe and effective when properly fitted, and that the design met military specifications. The company contended that hearing loss among veterans resulted from the inherently loud military environment rather than earplug defects.

3M attempted to shield itself from liability through Aearo Technologies' bankruptcy filing, but the bankruptcy court rejected this strategy, finding it was not filed in good faith. The failure of the bankruptcy approach, combined with mixed bellwether trial results, ultimately led to the $6 billion settlement.

3M agreed to pay $6 billion to resolve approximately 300,000 claims in August 2023 — one of the largest mass tort settlements in history.

Individual payment amounts vary based on hearing loss severity, tinnitus documentation, military service records, and exposure duration. The settlement uses a tiered compensation structure based on the nature and severity of documented auditory impairment.

3M also paid $9.1 million in 2018 to resolve a False Claims Act whistleblower suit (without admitting liability).

Past settlement amounts are not a guarantee of future results.