Demystifying Mass Torts: Coordinating Individual Claims and Designing Effective Resolution Processes

Mass tort litigation can appear daunting, even to experienced attorneys. Yet its central challenge is relatively straightforward: How can courts and parties address the factual and legal issues shared across many claims while still accounting for the circumstances of each claimant? Understanding that balance helps demystify these matters and reveals why alternative dispute resolution (ADR) can play an integral role in designing efficient, equitable paths toward resolution.

As of Aug. 3, 2026, more than 205,000 cases were pending in 162 active federal multidistrict litigations (MDLs), according to the U.S. Judicial Panel on Multidistrict Litigation.* Twenty-one of those MDLs involved at least 1,000 cases each. While these numbers do not include every mass tort case proceeding in federal and state courts, they offer a sense of the volume involved.

Managing a mass tort, however, involves more than handling a large number of cases. Courts and parties must coordinate common issues while preserving the individual nature of each claim.

What Is Mass Tort Litigation?

Simply stated, mass tort litigation involves many individuals bringing separate claims against the same defendant or group of defendants based on similar alleged injuries involving a product, drug, device, exposure or event. Common examples include pharmaceuticals and medical devices, consumer products, environmental contamination, toxic exposure, transportation incidents and natural disasters.   

Consider the kinds of stories that make national headlines: a medication linked to unexpected health effects, a widely used consumer product alleged to be defective or a train derailment that exposes nearby communities to hazardous materials. When the same product, event or exposure allegedly harms many people, the resulting claims may develop into mass tort litigation.

Although these claims share enough factual or legal overlap to make coordinated management useful, they generally remain individual. Causation, damages, defenses and applicable law may vary according to each claimant’s circumstances.

How Are Mass Torts Coordinated?

When related lawsuits are filed in federal courts around the country, they may be transferred to one federal district for coordinated or consolidated pretrial proceedings. This process, known as multidistrict litigation, or MDL, allows a single judge to oversee common matters such as discovery and other pretrial issues.

The cases generally remain individual lawsuits. Coordinating them can reduce duplicative work, promote consistency and preserve court and party resources.

As these matters progress, courts and parties may also use ADR to address common settlement questions, resolve discrete disputes or develop processes for evaluating individual claims. JAMS mediators, court-appointed neutrals (referee/special master) and other neutral professionals may assist with specific aspects of the litigation, settlement or claims administration process.

Mass Torts and Class Actions: The Key Distinction

Mass torts and class actions can both involve large numbers of people and common allegations, but they operate differently.

• Individual claims in mass torts: Each claimant typically maintains a separate action and must prove individual causation, injury and damages. Recoveries can differ based on the evidence and the terms of any resolution program.
• Representative litigation in class actions: Named plaintiffs litigate on behalf of a certified class under Rule 23 of the Federal Rules of Civil Procedure. Any judgment or settlement binds class members as the rule and the court’s orders provide, and distributions follow the court-approved plan.

This distinction is more than procedural. It explains why a mass tort resolution process must be sufficiently consistent to handle volume while remaining sufficiently flexible to account for material differences among claimants.

Why Resolution Becomes Difficult at Scale

The continued importance of individual claims distinguishes a mass tort from a class action, but it can also make resolution more complicated.

A global agreement may resolve common questions, but it rarely answers every claim-level issue. Claimants can differ in diagnosis, exposure, product use, medical history, timing, causation evidence, treatment, economic loss and applicable law. The available records may also vary substantially in completeness and reliability.

These differences create several recurring design questions:

• Who is eligible to participate?
• What proof is required?
• Which distinctions should affect valuation?
• How should incomplete or disputed claims be handled?
• What review rights are appropriate?
• How can the process remain understandable and administrable as the claimant population changes?

These questions illustrate why process design should begin early. If parties postpone operational issues until after agreeing on headline economics, they may discover that the proposed framework is too burdensome, rigid or ambiguous to implement. Moving from coordinated litigation to individual resolution requires not only agreement on settlement terms, but also a workable method for determining eligibility, documentation requirements and the treatment of meaningful differences among claims.

Where ADR Can Add Value

ADR can support a mass tort at several points in its life cycle. Mediation may help parties explore global terms, resolve discrete issues, narrow areas of disagreement or establish a structure for continued negotiation. Court-appointed neutrals (referee/special master) and other ADR professionals may assist with discovery disputes, privilege questions, settlement implementation or defined claim-level determinations.

Structured resolution programs can provide a framework for evaluating and resolving large numbers of individual claims. These programs may incorporate neutral panels, allocation procedures, review mechanisms and administrative processes tailored to the characteristics of the matter.

There is no single model that fits every mass tort. The appropriate combination of mediation, claims administration and process design depends on the maturity of the litigation, the number and nature of the claims, the quality of the available data, the relationship among the parties and the degree of individualized review required.

Whatever model is selected, the neutral’s role should be expressly defined, with clear authority and procedures for addressing conflicts or challenges.

Consistency Without Oversimplification

The central challenge is consistency without oversimplification: creating enough structure to manage a significant volume of claims while preserving the ability to consider meaningful differences among individual cases.

A successful process must be repeatable enough to manage a large claimant population, transparent enough to earn confidence and flexible enough to recognize material differences. ADR does not eliminate the tension between what is common and what remains individual, but it offers adaptable tools for addressing it—from early mediation and issue resolution to the design and administration of large-scale claims programs.

JAMS supports parties and counsel in complex, large-scale disputes through mediation, court-appointed neutrals (referee/special master) and other neutral services; administrative support; and customized resolution processes. Explore JAMS’ mass tort capabilities to learn more.

* U.S. Judicial Panel on Multidistrict Litigation, “Pending MDLs,” reports as of Aug. 3, 2026: https://www.jpml.uscourts.gov/pending-mdls-0