What is the difference between a mass tort and a class action?

In a mass tort, each plaintiff keeps a separate lawsuit and must still prove their own claim and damages, even though the cases are consolidated for efficiency. A class action combines plaintiffs into one suit led by a class representative whose result binds the entire class. Mass torts allow a more flexible approach and are often used when a class action is not permissible.

Who decides whether cases become a mass tort?

In the federal system, the Judicial Panel on Multidistrict Litigation — a group of federal judges — decides motions to consolidate. It weighs whether the cases share common legal issues, whether there are enough of them, and whether centralizing them before one judge would conserve judicial resources without prejudicing the parties. Many states have their own consolidation rules for in-state claims.

What kinds of injuries lead to mass torts?

Common examples include defective products, defective medical devices, dangerous drugs, commercial plane crashes, train derailments, industrial explosions, and environmental or groundwater contamination. These are situations where a single cause harms a large group of people in similar ways across multiple locations.

What Is a Mass Tort? | Morris & Dewett

Last reviewed: June 8, 2026 Morris & Dewett Injury Lawyers

A mass tort is a form of litigation that lets many plaintiffs who suffered similar injuries from the same circumstance pursue their claims together. It can cover a few dozen or tens of thousands of people, often spread across multiple states, who share similar claims against the same defendant. Consolidating these cases conserves resources and streamlines the process for everyone involved.

Understanding mass torts

Most mass torts arise when a single cause leads to widespread harm — for example, when a defective product injures thousands of people. Rather than each plaintiff litigating alone, the cases are joined so no one has to expend as much time and money proving the shared facts.

When the harm crosses jurisdictions, a court may consolidate the cases into multidistrict litigation (MDL), putting the matter before one judge. A federal district judge in one state can oversee a product liability proceeding affecting injured people nationwide. Even consolidated, each plaintiff must still prove their own claim and recover their own damages.

Examples of mass tort litigation

Mass torts commonly grow out of:

Defective product lawsuits
Defective medical device cases
Commercial plane crashes
Dangerous drug cases
Pollution and environmental contamination litigation
Explosions or industrial accidents
Groundwater contamination lawsuits
Train derailment lawsuits

Benefits and limitations

For plaintiffs who suffered similar injuries from the same cause, a mass tort offers real advantages:

Each plaintiff files and controls their own lawsuit
Each plaintiff recovers their actual damages, not a share divided among a class
Litigation costs are lower than going it alone
Discovery is faster and shared across cases
Experts and case information are easier to find and reuse
The chances of winning compensation improve

There are tradeoffs as well:

Reduced individual control during the discovery phase
Litigation may be seated in a distant court, requiring travel
The added complexity can lengthen the time to resolution

Weighing these pros and cons is easier with counsel who has handled mass tort litigation before.

How mass tort litigation works

Most mass torts begin with individual plaintiffs filing separate complaints against the same defendant. As those lawsuits pile up, either party or the court may move to consolidate them. The court decides whether consolidation is appropriate; if it is, one judge oversees the combined cases. Some defendants fight consolidation simply to drive up costs and pressure a low settlement — an experienced litigator anticipates that tactic.

In the federal system, the Judicial Panel on Multidistrict Litigation decides motions to consolidate. This panel of federal judges meets several times a year and weighs factors such as the commonality of legal issues, the number of related cases, whether the chosen jurisdiction is fair to all parties, and whether centralization conserves judicial resources without unreasonable delay or prejudice. Many states, including California and Pennsylvania, run similar processes for in-state claims.

Once a request is granted, the court sets a hearing to establish pretrial procedures, discovery plans, and other details. Mass tort discovery is extensive and complex, which is why these cases call for knowledgeable, experienced attorneys.

Mass torts versus class actions

People often confuse a mass tort with a class action, but they are different. A mass tort combines many separate cases for efficiency, yet each plaintiff must still prove their own claim and keeps control of their own lawsuit.

A class action, by contrast, merges plaintiffs — sometimes thousands or millions with a nearly identical claim — into a single suit led by a class representative. Whatever that representative wins or loses binds the entire class. Because class actions follow strict guidelines, mass torts are frequently used when a class action is not permissible and a more flexible structure is needed.

If you and many others were hurt by the same product, drug, or disaster, a mass tort may be the right path to compensation. An injury lawyer can tell you whether your case fits and what consolidation would mean for your claim.

Frequently Asked Questions

What is the difference between a mass tort and a class action?: In a mass tort, each plaintiff keeps a separate lawsuit and must still prove their own claim and damages, even though the cases are consolidated for efficiency. A class action combines plaintiffs into one suit led by a class representative whose result binds the entire class. Mass torts allow a more flexible approach and are often used when a class action is not permissible.
Who decides whether cases become a mass tort?: In the federal system, the Judicial Panel on Multidistrict Litigation — a group of federal judges — decides motions to consolidate. It weighs whether the cases share common legal issues, whether there are enough of them, and whether centralizing them before one judge would conserve judicial resources without prejudicing the parties. Many states have their own consolidation rules for in-state claims.
What kinds of injuries lead to mass torts?: Common examples include defective products, defective medical devices, dangerous drugs, commercial plane crashes, train derailments, industrial explosions, and environmental or groundwater contamination. These are situations where a single cause harms a large group of people in similar ways across multiple locations.