UNITED STATES DISTRICT COURT

NORTHERN DISTRICT OF FLORIDA

PENSACOLA DIVISION

IN RE: 3M COMBAT ARMS 

EARPLUG PRODUCTS

Case No. 3:19md2885

LIABILITY LITIGATION

This Document Relates to All Cases Judge M. Casey Rodgers

Magistrate Judge Hope T. Cannon

NOTICE

On February 23, 2023, a Data Day proceeding was held at which 

BrownGreer PLC presented its neutral analyses of the nature and scope of the 

hearing-related claims in this litigation as reflected in the available audiometric 

data for the plaintiff population in DOEHRS. At the Court’s direction, 

BrownGreer analyzed the data using four methods—the two party approaches as 

understood by the Court (the single frequency/threshold shift approach used by 

Plaintiffs, and the pure tone average-based approach used by 3M), and a variation

of each side’s approach that better accounts for timing of CAEv2 use relative to 

the plaintiffs’ reported hearing-related injuries. A copy of BrownGreer’s 

Powerpoint presentation was previously posted on the Court’s public website for 

the MDL.1

 

1 See https://www.flnd.uscourts.gov/file/data-day-presentation-2-23-23pdf. 

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As the Court explained at Data Day, BrownGreer also was asked to perform 

the same set of analyses—again, the two party methods and the two Court 

methods—on a random sample of 500 plaintiffs from the inventory with available

census and DOEHRS data, which it has now done.

2

 Of particular note, the 

analyses revealed that applying the four methods to a random sampling of 

qualifying plaintiffs yields roughly identical percentages of hearing-related 

injuries as resulted from BrownGreer’s original analyses of the entire plaintiff 

population. A copy of the results of BrownGreer’s new analyses will be posted 

on the Court’s public website for the MDL. 

Of course, as the Court previously observed, there are strengths and 

weaknesses inherent in all four methods. 3M’s pure tone average-based approach, 

for example—and we know it remains 3M’s approach based on its recent public 

statements and the estimation motion filed in Aearo’s bankruptcy proceedings3

—

2 More specifically, BrownGreer first separated the overall plaintiff population into two 

groups, one group comprised of plaintiffs asserting hearing loss only or a combination of 

hearing loss and tinnitus, and a second group comprised of plaintiffs asserting tinnitus only. 

For each group, BrownGreer then narrowed the pool to only plaintiffs with enough census and 

DOEHRS data to calculate a result under all four methods. Last, BrownGreer randomly 

selected 500 plaintiffs from the remaining population in each of the two groups (for a total of 

1,000 plaintiffs), and used only those plaintiffs in its new analyses.

3 See In re Aearo Techs. LLC, No. 1:22bk2890, Debtors’ Motion for Entry of an Order 

(I) Authorizing Estimation of the Aggregate Value of Combat Arms-Related Claims for the 

Purposes of Establishing a Settlement Trust and Confirming a Plan Under Chapter 11; (II) 

Scheduling Claims Estimation Proceedings; and (III) Granting Related Relief, ECF No. 1221 

at 2-3, 6-8, 16 (Feb. 28, 2023); Press Release, 3M Co., Department of Defense Data Reveals 

No Hearing Loss Among Vast Majority of Plaintiffs in Combat Arms Earplug Litigation (Mar. 

1, 2023), available at https://investors.3m.com/news/news-details/2023/Department-ofCase 3:19-md-02885-MCR-HTC Document 3696 Filed 03/10/23 Page 2 of 4
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excludes the two frequencies (4000 and 6000 Hz) most commonly affected by 

noise and includes two frequencies (500 and 1000 Hz) rarely affected by noise, 

which is problematic in a litigation where the alleged injury is noise-induced 

hearing damage. Moreover, even the pioneers of pure tone average rating 

schemes, the World Health Organization and American Medical Association, 

caution against relying on the schemes for diagnostic purposes and/or as the sole 

determinant in assessing a person’s hearing-related damage.

4

 Plaintiffs’

approach, which focuses only on the presence of hearing threshold shifts in the 

audiometric data, does not distinguish between temporary versus permanent 

shifts, and does not measure or value an individual’s current hearing loss status

(i.e., normal, slight, mild, moderate, moderately severe, severe, profound). 

Neither side’s approach accounts for specific causation. To the extent those 

Defense-Data-Reveals-No-Hearing-Loss-Among-Vast-Majority-of-Plaintiffs-in-CombatArms-Earplug-Litigation/default.aspx; 3M Co., Setting the Record Straight: 3M, the Military 

and Combat Arms Earplugs Version 2, available at https://www.3mearplugsfacts.com/.

4 See, e.g., World Health Organization, World Report on Hearing at 38 (2021) (“The 

classification and grades [of hearing loss] are for epidemiological use[.]”); id. (“While 

audiometric descriptors (e.g. category, pure-tone average) provide a useful summary of an 

individual’s hearing thresholds, they should not be used as the sole determinant in the 

assessment of disability[.]”); American Medical Association, Guides to the Evaluation of 

Permanent Impairment § 1.3d (“In disability evaluation, the impairment rating is one of several 

determinants of disablement.”); id. at § 2.3b (explaining that “assessing [an] impairment’s

impact on [an] affected individual’s ability to work . . . is beyond the scope of the Guides”); id. 

at § 11.2d (“The Guides’ methods for calculating [hearing] impairment are not intended to 

examine an individual’s work disability[.]”); see also Lambdin v. Goodyear Tire & Rubber Co., 

468 S.W. 3d 1, 14 (Tenn. 2015) (“The AMA Guides do not make any mention of hearing losses 

at levels exceeding 3000 hertz . . . In that regard, the AMA Guides do not “cover” [noiseinduced hearing] injury.”).

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methods, or any others, are offered to a neutral as a basis for valuing and/or 

estimating claims, the Court trusts the parties will heed their duty of candor to the 

court and the public as to the relative merits of each one. 

SO ORDERED, on this 10th day of March, 2023. 

M. Casey Rodgers M. CASEY RODGERS

 UNITED STATES DISTRICT JUDGE

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