Unmasking PFAS

The product identification process presently under way in the Aqueous Film-Forming Foam (AFFF) multidistrict litigation (MDL) offers an innovative application of discovery practices used in other complex litigation and toxic tort actions in assessing manufacturer defendants' potential liability in the MDL.

In deviating from pure market-share liability principles while applying product identification discovery practices used in national tobacco and toxic tort litigation, the AFFF MDL product identification discovery plan aims to collect extensive data from a representative pool of "sites" concerning the presence (or absence) of particular chemical products at these "representative sites."

The selection of these "representative sites" considers the variety of plaintiffs in the MDL (including government municipalities, public water providers, industrial sites, private property owners, and individuals) and that the source of every potential exposure would be difficult, if not impossible, to identify (unlike, for example, in an individual asbestos case).

In approving the representative sites, the court instructed that the pool of sites must be large enough to be meaningful. For the information collected from these sites to be "meaningful," it must be sufficiently representative to eventually be extrapolated across all cases pending in the MDL to streamline issues of causation and potential liability. However, the court also cautioned that the pool of sites must not be so large as to be disproportionately burdensome to the benefit of the information being gathered.

Under this scheme, absent product identification, the causal nexus between a plaintiff's alleged harm and a defendant's alleged conduct cannot lie. This product identification process is a pivotal development in the apportionment of liability against manufacturers because without product identification, a manufacturer's respective market share would be rendered immaterial in a traditional sense and the lawsuit against it properly dismissed.

Contextualization of Pending PFAS AFFF Litigation
In December 2018, the Judicial Panel on Multidistrict Litigation formed the polyfluoroalkyl substances (PFAS) AFFF MDL and appointed the Honorable Richard M. Gergel, U.S. District Court for the District of South Carolina, to oversee the MDL for coordinated discovery and pretrial litigation. More than 10,000 cases are presently pending in the MDL against hundreds of manufacturers, importers, suppliers, and retailers.

These lawsuits primarily allege personal injury and/or property damage caused by exposure to AFFF containing perfluorooctanoic acid (PFOA) and/or perfluorooctane sulfonate (PFOS) through various channels. The most common, but not exclusive, channel of exposure is contaminated groundwater near thousands of airports, military bases, firefighting training centers, and other industrial sites where AFFF was used to extinguish "liquid fuel fires."
PFOA and PFOS are different types of PFAS with slightly differing chemical structures. PFAS is often defined as a "complex group of synthetic chemicals" containing "at least one fully fluorinated carbon atom." This fluorocarbon molecular structure potentially makes it difficult for the chemical to degrade naturally in the environment.

What Is Product Identification?
Different domestic and foreign manufacturers have occupied the market for research, development, manufacture, and sale of AFFF and/or its chemical components, which may have been used at various sites over time.

"Product identification" refers to the process of ascertaining (a) the particular AFFF product(s); (b) the manufacturer of said AFFF product(s); (c) the manufacturer of the PFAS that was used in manufacturing the AFFF; (d) which was discharged at a particular site; (e) during a relevant time period.

Following years of litigation, in late 2024, Judge Gergel observed that "the time has...arrived" to address these pervasive product identification challenges inherent in personal injury claims, cases brought by public water providers, soil contamination, and sovereign state claims alike. Acknowledging the impracticality of undergoing a targeted product identification investigation at each contaminated site, the court instructed parties to jointly propose a "representative sample pool" of sites to undergo "robust product identification discovery."

On Jan. 15, 2025, the court entered Case Management Order No. 32 (CMO 32), which approved the parties' "product identification protocol," and established the process for selecting 10 to 15 eligible sites to be jointly submitted to the court. CMO 32 "primarily include[d] airports, fire training centers, and/or other locations where AFFF was used[,]" and delineated the parameters of product identification discovery at the approved sites.

Per the terms of CMO 32, parties jointly proposed 12 sites that were approved by the court on April 1, 2025. This product identification discovery is presently under way and will run for six months through October 1, 2025. CMO 32 provides for the traditional product identification (PID) tools including tailored written and documentary discovery in the form of limited interrogatories and requests for production directed to each party involved in discovery at a particular site; limited party depositions pertaining to each site; and unlimited non-party discovery (both documentary and testimonial) pertaining to each site.

Thirty days prior to the conclusion of the PID discovery period (September 2025), "the parties shall begin to confer further on a process to address partial dismissals, if any, that may occur following the product ID discovery and any further proceeding as may be warranted as to these cases or any subset of such cases." Judge Gergel was unequivocal in his expectation that if, upon conclusion of the PID process, a defendant's product is notidentified, claims against that defendant shall be dismissed. This expectation is akin to asbestos litigation and corresponding CMOs requiring dismissal of unidentified defendants at the close of discovery. By leaving only identified defendants, the parties can "simplify" this particularly complex litigation for both trial and settlement.

Significance of Product Identification Discovery for Early Case Resolution and Judicial Efficiency
Despite this innovative approach of building upon traditional foundational principles of market-share liability to apportion liability against manufacturers in mass tort and complex litigations based on demonstrated exposure to particular defendants' product(s) at representative sites, the PID protocol still holds plaintiffs to their burden of establishing both general causation (that PFAS exposure caused the type of harm alleged) and specific causation (that exposure to PFAS that was manufactured by a particular defendant caused the plaintiff's alleged harm such that an adverse finding of liability against that defendant is fair). But this approach also potentially offers clearer information as to a defendant's potential liability.

Under this innovative discovery protocol, equity ensures that a defendant entitled to dismissal (i.e., a defendant lacking a nexus to alleged PFAS exposure/contamination at a particular site) is not compelled to bear undue litigation costs through the time of trial. Absent a showing of PID, a manufacturer's respective global market share fails to confer a basis for any adverse finding of liability in accordance with the interests of fairness and due process. On the other hand, the defendant that is identified can now devote its energy to questions of causation and, if warranted, considerations of settlement.

Aptly developed to illustrate the historic use and/or release of PFAS AFFF at each representative site, neither the court nor the parties have yet to publicly identify "next steps" in the PID process. We anticipate that these next steps will contemplate how the collected data from the PID process will be fairly and accurately extrapolated across the thousands of sites and hundreds of defendants involved in the MDL. Contemplation of this next phase likely will not begin until after the Oct. 1, 2025, close of PID discovery.

Though labor intensive and highly technical, investment in this evolving PID discovery process is expected to foster early case resolution in thousands of cases where product identification may be established without overburdening litigants and judicial resources with a trial of each action on the merits (either upon selection as a bellwether case or on remand to the court of original jurisdiction), and where appropriate, require dismissal(s) against manufacturers that might otherwise be penalized under traditional principles of market-share liability.

This article has been published in the July 14, 2025, posting of CLM Magazine.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.