A mass tort is a civil proceeding in which many people harmed by the same product, drug, device, or event each file their own individual lawsuits, which a court then manages together for efficiency. What is a mass tort in practical terms? It is a way for large groups of injured people to share the heavy lifting of litigation — discovery, expert witnesses, pretrial motions — while each person keeps a separate case and recovers based on their own injuries. Most federal mass torts move through a coordinated process called multidistrict litigation, which handled over 37,000 individual cases in fiscal year 2025 alone.1United States Courts. Judicial Panel on Multidistrict Litigation – Judicial Business 2025
Mass Tort vs. Class Action
People routinely confuse the two because both involve groups of injured people suing the same defendant. The difference matters once you start thinking about what you might actually recover.
A class action is a single lawsuit. One or a few named plaintiffs represent an entire group of similarly situated people under Rule 23 of the Federal Rules of Civil Procedure, which requires the class to be large enough that individual suits would be impractical and the claims to share common legal and factual questions.2Legal Information Institute. Federal Rules of Civil Procedure Rule 23 – Class Actions Class members generally don’t make individual strategy decisions, and if the case settles, the recovery gets divided across all members — sometimes equally, sometimes by formula, but rarely in a way that reflects the full severity of any one person’s injuries.
A mass tort keeps every plaintiff’s case separate. Your attorney presents evidence specific to your injury, your medical history, and your financial losses. Someone with a permanent disability and someone with a temporary reaction are not treated identically. Settlements vary dramatically from plaintiff to plaintiff within the same litigation, and preserving that individual valuation is the whole point. The tradeoff is time and cost: mass torts take longer to litigate because each case needs its own factual development. For people with serious injuries, that tradeoff usually pays off.
Common Types of Mass Tort Cases
Mass torts tend to cluster around a few recurring categories.
Dangerous pharmaceuticals are one of the biggest. A drug reaches the market, causes side effects that weren’t disclosed or were downplayed, and thousands of people develop the same health problems. Defective medical devices follow a similar pattern — hip implants that deteriorate inside the body, surgical mesh that causes chronic pain, heart devices that malfunction. In both categories, the central allegation is that the manufacturer knew or should have known about the risk and failed to warn patients.
Consumer products that injure large numbers of people also generate mass torts: contaminated food, children’s items with toxic materials, household goods that catch fire. Environmental contamination is another major source, often involving chemical spills, industrial pollution, or water supplies tainted with substances like PFAS, lead, or benzene. These cases often affect entire communities, and the health effects may not surface for years. What ties all of them together is a single defendant whose product or conduct injured many people in related ways.
How Multidistrict Litigation Coordinates the Cases
When mass tort cases are filed in federal courts across the country, they are typically consolidated into a single proceeding called multidistrict litigation, or MDL. Under 28 U.S.C. § 1407, when civil cases in different federal districts share common factual questions, the Judicial Panel on Multidistrict Litigation can transfer them all to one court for pretrial proceedings.3Office of the Law Revision Counsel. 28 US Code 1407 – Multidistrict Litigation The idea is to avoid the waste of dozens of judges running the same discovery disputes and reaching inconsistent rulings on the same legal questions.4United States Judicial Panel on Multidistrict Litigation. About the Panel
Once the cases land in a single court, the assigned judge manages all pretrial work: discovery, expert witness disputes, motions to dismiss, and the other procedural battles that would otherwise be duplicated across every district. The judge also appoints a leadership committee of plaintiff attorneys to coordinate strategy, run discovery, and negotiate on behalf of everyone.
MDL only covers pretrial proceedings. If cases aren’t resolved through settlement or dismissal, they get sent back to the courts where they were originally filed for individual trials.3Office of the Law Revision Counsel. 28 US Code 1407 – Multidistrict Litigation In practice, most cases settle during the MDL phase. The process is designed to build enough information and leverage that the parties can reach a resolution without thousands of separate trials.
What Bellwether Trials Do
Before most mass torts reach a global settlement, the MDL judge picks a small set of individual cases to go to trial first. These are bellwether trials, and the Federal Judicial Center describes them as individual trials “conducted by MDL transferee judges with the goal of producing reliable information about other cases centralized in that MDL proceeding.”5Federal Judicial Center. Bellwether Trials in MDL Proceedings – A Guide for Transferee Judges
Selection matters. The judge and attorneys identify key characteristics across all the cases in the MDL and build a pool of claims that represent the full range, not just the strongest or weakest. From there, specific cases are chosen by the parties, the judge, or a randomized method. If one side cherry-picks only its best cases, the results won’t say much about the litigation as a whole, and the judge can override those picks.5Federal Judicial Center. Bellwether Trials in MDL Proceedings – A Guide for Transferee Judges
Bellwether verdicts shape what happens next. When juries consistently side with plaintiffs and award significant damages, defendants face pressure to settle the remaining cases rather than face thousands of similar outcomes. When defense verdicts dominate, plaintiffs may accept lower offers or drop weaker claims. Either way, the results give both sides a realistic picture of what juries think, and that picture drives settlement negotiations across the MDL.
Who Qualifies for a Mass Tort Claim
Joining a mass tort requires three things, and all three have to be documented.
First, proof of exposure. You need evidence that you actually used the drug, received the implant, or lived in the affected area. Pharmacy records, medical device registration, or residential records typically do the job.
Second, a diagnosed injury consistent with the type of harm the product or event is known to cause. A mass tort over a blood-thinning drug that caused internal bleeding requires plaintiffs who experienced bleeding events, not unrelated conditions. Medical records and sometimes expert medical testimony establish this element.
Third, causation: a link between your exposure and your injury strong enough to hold up in court. This is usually the hardest element and the one where cases fall apart. Showing you took the drug and later got sick isn’t enough. You need evidence, often through expert witnesses, that the product or event was the probable cause of your specific injury rather than some other factor. The strength of this connection directly affects both eligibility and the value of your claim.
Filing Deadlines and the Discovery Rule
Every mass tort claim is subject to a statute of limitations. Miss it, and your claim is gone no matter how strong it is. These deadlines vary by state and claim type, but they generally run from one to six years.
The complication in mass tort cases is that injuries often surface long after exposure. Someone taking a prescription drug for years may not develop symptoms until a decade later. A community exposed to contaminated groundwater might not connect their health problems to the contamination for years. If the clock started at exposure, many people would be barred before they even knew they were injured.
Most states address this through the discovery rule, which delays the start of the limitations period until you knew or reasonably should have known about your injury and its likely cause. The clock starts when a reasonable person in your situation would have connected the dots — not necessarily when you got a formal diagnosis, but when the signs were clear enough that you should have investigated. If you’re even considering a mass tort claim, this is where delay can cost you everything. Talk to an attorney early. The discovery rule involves factual judgments that vary by jurisdiction, and what counts as “should have known” is often the single most contested issue.
What Compensation Looks Like
Because each plaintiff keeps an individual claim, compensation is calculated on your particular losses. Two people in the same litigation can receive very different amounts depending on injury severity, treatment costs, and long-term impact.
Economic and Non-Economic Damages
Economic damages cover financial losses you can document: past and future medical bills, lost wages, reduced earning capacity, and out-of-pocket costs like travel for treatment. Non-economic damages compensate for harm that doesn’t come with a receipt — pain, emotional distress, loss of enjoyment of life. The more severe and permanent the injury, the higher both categories tend to run.
Punitive Damages
In some mass torts, courts award punitive damages on top of compensatory damages. These are not meant to compensate you for a loss. They are meant to punish the defendant for particularly reckless or deliberate misconduct and to discourage similar behavior. A drug manufacturer that buried evidence of fatal side effects, for example, might face punitive damages that dwarf the compensatory awards. Not every mass tort involves them, but when internal documents reveal that a company knowingly put a dangerous product on the market, the potential rises sharply and often pushes defendants toward settlement.
Tax Treatment
Federal tax law excludes from gross income any damages (other than punitive damages) received on account of personal physical injuries or physical sickness. If your claim involves a physical injury — a failed medical device, a drug that caused organ damage, chemical exposure that led to cancer — your compensatory settlement is generally tax-free. Compensation for emotional distress alone, without an underlying physical injury, does not qualify for the exclusion, though you can exclude the portion that reimburses you for medical care related to the emotional distress.6Office of the Law Revision Counsel. 26 USC 104 – Compensation for Injuries or Sickness Punitive damages are always taxable. Given the amounts involved in many mass tort settlements, paying for tax advice before agreeing to a settlement structure is worth it.
Attorney Fees and Litigation Costs
Mass tort attorneys almost universally work on contingency, meaning you pay nothing upfront. The attorney advances all litigation costs and takes a percentage of your recovery only if you win or settle. That percentage typically falls between 33% and 40%, with the exact figure depending on your agreement and when the case resolves. Cases that go to trial generally carry a higher percentage than those that settle early.
There is one cost unique to MDL proceedings worth knowing about: the common benefit assessment. The lead attorneys who coordinate discovery, hire experts, and run bellwether trials on behalf of all plaintiffs invest enormous time and resources. Courts compensate that work by ordering a percentage — typically 3% to 6% of each plaintiff’s gross settlement — into a common benefit fund. The important part is that this assessment generally comes out of your individual attorney’s fee, not as an additional charge on top of it. Your attorney absorbs it from their contingency share. Separately, litigation costs like filing fees, expert witness charges, and deposition expenses are deducted from your settlement proceeds, so the net amount you receive is always less than the gross figure. Ask your attorney for a clear written breakdown of all potential deductions before you sign a retainer.
How Long Mass Torts Take
The timeline is what catches most people off guard. Mass torts routinely take years to resolve, and complex ones can stretch beyond a decade. The pretrial phase alone — consolidation, discovery, expert battles, bellwether trials — often runs several years before any global settlement discussions gain traction. During that time, no money changes hands.
The length depends on the number of plaintiffs, the complexity of the scientific evidence, how aggressively the defendant fights, and whether bellwether trials produce clear enough results to push both sides toward settlement. Some plaintiffs receive compensation within three to five years. Others wait much longer, particularly where causation is contested or the defendant appeals adverse rulings. Knowing this upfront lets you plan realistically and avoid the frustration that pushes some plaintiffs into accepting lowball offers.