The federal judge in charge of the multidistrict litigation (MDL) against 3M and Aearo Technologies has issued an order demanding that both the plaintiffs and defendants “heed their duty of candor” with respect to the data determining eligibility for membership in the MDL. This order comes soon after a March 1 estimation filed by Aearo Technologies which argued that the “vast majority” of plaintiffs did not have hearing damage, according to Law360.

According to U.S. District Judge M. Casey Rodgers, 3M’s evaluation of plaintiffs using a pure tone average approach is flawed. In her order, Judge Rodgers notes that this test excludes the two frequencies – 4000 Hz and 6000 Hz – most commonly impacted by noise-related hearing loss.

Additionally, 3M’s analysis took an average using two frequencies, 500 Hz and 100 Hz, which are rarely ever impacted by noise. In Judge Rodger’s own words, the analysis is “problematic in a litigation where the alleged injury is noise-induced hearing damage.” Furthermore, Judge Rodgers notes that even the innovators of the pure tone average ratings, the World Health Organization and American Medical Association, warn that it should not be relied on as the sole factor for diagnosing or determining a person’s hearing damage. 

On the other side, Judge Rodgers criticized the plaintiff’s methodology for finding hearing loss. Judge Rodgers notes that the plaintiff’s approach “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).”

In total, Judge Rodgers found both parties’ accounts lacking, as neither one accounted for the type of specific causation needed for a clear litigatory decision.

In addition to hearing the examinations conducted by the plaintiffs and defendants, Judge Rodgers ordered a neutral third party, BrownGreer, to conduct analysis using both parties’ methods and two court-determined methods to objectively assess the number of valid hearing loss claims. 

In a 73-slide PowerPoint, BrownGreer describes how it used census forms and Defense Occupational Environmental Health Readiness System (DOEHRS) data to create a dataset of 178,040 plaintiffs that measured hearing loss from the audiograms dated near the time that plaintiffs would have been using CAEv2 earplugs, to audiograms dated near the time that plaintiffs would have stopped using the earplugs. This was not a complete sample and 56,588 were not included either because they did not return DOEHRS data, the data was still pending, or the requests for data had not been submitted at the time of analysis.

Using the plaintiffs’ methods, BrownGreer identified 104,625 plaintiffs with qualifying hearing loss claims. However, when the method was refined using audiograms from the window of time associated with CAEv2 earplug use, the number of qualifying plaintiffs shrank to 62,111. Using 3M’s method of detection, BrownGreer identified only 16,017 qualifying plaintiffs and when the methodology was refined for the court’s process, that number shrank to 7,381.

In her closing comments, Judge Rodgers called on both sides to “heed their duty of candor to the court and the public as to the relative merits” of either side’s methodology. This order serves as a reminder to 3M and the hearing loss plaintiffs that they must stick close to the facts in the presentations of their cases.