TL;DR - Multidistrict litigation (MDL) is a federal procedure that consolidates thousands of similar lawsuits before a single judge for coordinated pre-trial proceedings. - The Judicial Panel on Multidistrict Litigation (JPML), a panel of seven federal judges, decides which cases are consolidated and where. - Unlike a class action, every plaintiff in an MDL keeps their own individual case and their own damages calculation. - MDLs now make up more than half of all pending federal civil cases in the United States. - Most large mass tort MDLs end in a global settlement negotiated after bellwether trials establish the value of the claims.
Picture this: a pharmaceutical company sells a drug that causes serious injuries in tens of thousands of patients across the country. Plaintiffs begin filing lawsuits in Texas, Florida, New Jersey, California, and dozens of other states. Each court starts its own discovery process. Each judge makes different rulings on the same evidence. Defendants face the same depositions hundreds of times over in different cities. Plaintiffs' attorneys, working individually, cannot afford the expert witnesses that a coordinated effort could share.
Multidistrict litigation exists to solve exactly this problem. When civil cases across multiple federal districts share common factual questions, they can be transferred to a single federal judge who manages all pre-trial proceedings in one place. The result is faster, fairer, and far less expensive for everyone involved.
This guide explains what multidistrict litigation is, how the process works from first motion to final settlement, and what it means for the hundreds of thousands of Americans whose cases are currently pending inside an MDL.
What is multidistrict litigation?
Multidistrict litigation (MDL) is a federal legal procedure that consolidates civil cases from different districts before one judge for coordinated pre-trial proceedings, while each plaintiff retains their own individual case and their own right to individual damages.
The statutory basis is 28 U.S.C. § 1407, which gives a specialized panel of federal judges the authority to transfer cases sharing common factual questions into a single consolidated proceeding. The consolidation covers pre-trial activity only. Each plaintiff's case remains legally separate, and damages are assessed individually based on that person's specific injuries and circumstances.
This is the feature that distinguishes MDL from a class action. In a class action, one verdict or settlement applies uniformly to an entire class. In an MDL, a plaintiff who suffered severe injuries and a plaintiff who suffered mild injuries do not receive the same payment. Their cases move through the same pre-trial process together, but their outcomes are calculated separately.
Why MDL exists
The MDL statute did not emerge from abstract legal theory. It emerged from a crisis.
In the early 1960s, a price-fixing scandal in the electrical equipment industry produced 1,912 civil cases filed across 36 federal districts simultaneously. The federal court system had no mechanism to coordinate them. Chief Justice Earl Warren appointed an emergency coordinating committee in January 1962, chaired by Judge Alfred P. Murrah, which developed the practices that became the foundation for modern MDL procedure.
Congress turned those emergency measures into permanent law on April 29, 1968, when President Lyndon B. Johnson signed 28 U.S.C. § 1407 into law. The statute created the Judicial Panel on Multidistrict Litigation as a standing body and established the framework still used today.
The scale of MDL has grown far beyond what Congress anticipated in 1968. By 2018, 51.9 percent of all pending federal civil cases were consolidated into MDLs: 156,511 cases out of 301,766 total. Products liability cases, the category that includes pharmaceutical injuries and defective medical devices, account for 91 percent of the total MDL caseload.
How does an MDL lawsuit get started?
An MDL begins when a party files a motion asking the Judicial Panel on Multidistrict Litigation to consolidate related cases before a single judge.
Any party to a qualifying case can file the motion: plaintiffs, defendants, or even the court itself. The JPML is a panel of seven federal circuit and district court judges appointed by the Chief Justice of the Supreme Court. It meets several times a year in different cities across the country to hear transfer petitions and decide whether consolidation is appropriate.
The Panel's core question is whether the cases share common factual questions and whether consolidation would serve the convenience of the parties and witnesses while promoting the just and efficient conduct of the litigation. If the answer is yes, the Panel selects a transferee court and judge, and all qualifying cases are transferred there.
Cases filed after the initial consolidation order, called tag-along actions, are routinely swept into the MDL once identified. A plaintiff who files a new lawsuit against the same defendant for the same type of injury will typically find their case transferred automatically to join the existing MDL.
What happens once an MDL is formed?
Once the JPML issues a transfer order, all consolidated cases move to the transferee judge, who takes over full management of pre-trial proceedings for the entire MDL.
The transferee judge appoints lead counsel, sometimes called a plaintiffs' steering committee, to coordinate discovery and pre-trial motions on behalf of all plaintiffs. Individual plaintiffs retain their own attorneys, but lead counsel handles the shared work: obtaining documents from the defendant, deposing key witnesses, retaining and presenting expert testimony, and arguing motions that affect every case in the MDL.
The full nine-stage process from the first individual injury to final distribution of settlement funds is outlined in detail on the how it works page of this site. The consolidation stage is Stage 4. Everything from Stage 5 onward happens inside the MDL.
The nine stages of an MDL
Understanding where MDL fits in the broader timeline helps set realistic expectations. The nine stages are:
1. Individual injury occurs. A person is harmed by a drug, medical device, or toxic exposure, sometimes years before the connection to the product is understood. 2. Pattern of injuries identified. Medical researchers, the FDA, or plaintiff attorneys recognize a pattern of similar injuries linked to the same source. 3. Individual lawsuits filed. Plaintiffs file separate cases across multiple courts within the applicable statute of limitations. 4. JPML consolidates cases into an MDL. The Panel transfers federal cases to a single district, typically within two to six months of the motion to transfer. 5. Discovery phase. Both sides exchange documents, depose witnesses and experts, and argue Daubert motions to determine which expert testimony will be admissible at trial. This phase typically spans one to three years. 6. Bellwether trials. A small number of representative cases go to trial. Verdicts are not binding on other plaintiffs but establish how juries respond to the evidence and what the claims are worth. A full explanation is available in the guide to bellwether trials on this site. 7. Settlement negotiations. Parties use bellwether results to negotiate a global settlement covering remaining claims. 8. Claims administration. Plaintiffs submit documentation verifying their injuries and exposure for individual compensation review. 9. Distribution of funds. Qualifying plaintiffs receive payments after deducting attorney fees and resolving any medical liens.
The full process typically spans 4 to 7 years from MDL formation to final distribution, though some MDLs run longer.
What is the difference between MDL and a class action?
In a class action, one court proceeding resolves claims for an entire class of plaintiffs, and a single verdict or settlement applies to everyone who qualifies as a class member.
In an MDL, each plaintiff keeps their case with individually calculated damages. The MDL pools the pre-trial work, but it does not merge the cases into one. A plaintiff with severe, long-term injuries will receive a different settlement offer than a plaintiff with minor injuries, even if their cases moved through the same MDL together.
This distinction matters practically. Plaintiffs in an MDL have more control over their individual claims than class action members do. They can in theory reject a settlement offer and pursue their case individually, though this is rare once a global settlement is in place. They are not automatically bound by what the majority of plaintiffs decide.
For a full side-by-side breakdown of the two structures, see the comparison guide on this site.
What is the largest MDL in history?
The largest MDL by case count is the asbestos personal injury MDL (MDL No. 875), established in 1991 in the Eastern District of Pennsylvania. By 2011, it had received over 121,000 transferred cases, with more than 108,000 resolved through settlement or dismissal and approximately 13,000 still pending at that point.
For a single-product MDL, the 3M Combat Arms Earplugs litigation exceeded 300,000 claims, making it the largest single-defendant mass tort MDL in US history before its resolution.
Products liability cases, the category that covers pharmaceutical injuries, defective medical devices, and toxic exposure claims, represent 91 percent of total MDL caseload by volume. Antitrust cases are the second largest category but involve far fewer individual claimants. The mass tort cases most ordinary Americans encounter, prescription drugs, medical implants, environmental contamination, are almost entirely products liability MDLs.
How does multidistrict litigation end?
Most MDLs end in one of three ways: a global settlement, remand of cases to home courts for individual trial, or dismissal of claims that cannot be substantiated.
Global settlement is by far the most common outcome in large mass tort MDLs. After bellwether trials establish the value and strength of the claims, defendants and plaintiffs' lead counsel negotiate a settlement fund that covers all or most remaining cases. Individual plaintiffs then submit documentation to a claims administrator who calculates their specific payment based on injury severity, exposure duration, and other factors.
Cases that do not settle are remanded, meaning sent back, to their original home districts for trial. A 1998 Supreme Court ruling in Lexecon established that transferee judges cannot try cases themselves without the parties' consent. The transferee court manages pre-trial work, but trial must happen in the district where the plaintiff originally filed.
In practice, few mass tort cases reach individual trial. The economics of global settlement, combined with the information produced by bellwether trials, typically bring both sides to a negotiated resolution.
Active MDL lawsuits in the United States
More than 150 MDLs are currently pending in federal courts across the country. The active cases page on this site tracks the mass tort MDLs most likely to affect ordinary Americans, including:
- Talcum powder (Johnson and Johnson): ovarian cancer and mesothelioma claims; federal bellwether trials proceeding after J&J's bankruptcy strategy was rejected in March 2025.
- Roundup (Bayer/Monsanto): non-Hodgkin's lymphoma claims; global settlement of approximately $11 billion reached after three bellwether plaintiff wins.
- Camp Lejeune water contamination: processed through an administrative track under the PACT Act rather than a traditional bellwether structure.
- Depo-Provera: intracranial meningioma claims against Pfizer; MDL formed in 2024.
- AFFF firefighting foam (PFAS): cancer claims against foam manufacturers; multiple settlement funds in place.
- Social media addiction: youth mental health claims against Meta, TikTok, Snap, and YouTube.
Each of these MDLs is covered in depth on the individual case pages of this site, with current litigation status, settlement figures, and eligibility information updated regularly.
What MDL means for your individual claim
If your case has been consolidated into an MDL, the most important thing to understand is that your claim remains yours. Your specific injuries, your documented exposure, and your individual circumstances determine what you may receive. The MDL structure is not a class action that averages out everyone's damages.
The practical effect of being in an MDL is access to resources that no individual plaintiff could afford alone. Lead counsel has obtained millions of internal documents from defendants, deposed corporate executives, and retained the world's leading expert witnesses in the relevant medicine and science. Your individual attorney draws on all of that shared work when building your specific case.
Attorney fees in mass tort MDLs typically follow a contingency structure: 33 to 40 percent of any recovery, with no fee owed if the case is unsuccessful. Lead counsel who managed shared pre-trial work may also receive a common benefit fee of 4 to 8 percent, which is typically deducted from the overall settlement fund rather than added on top of individual attorney fees.
The timeline is long. Four to seven years from MDL formation to final payment is a reasonable expectation for most large mass tort cases, and some run longer. The glossary on this site explains the key terms you will encounter throughout the process, including MDL, JPML, bellwether trial, transferee judge, and claims administrator.
The information on mass-torts.com is for general informational purposes only and does not constitute legal advice. No attorney-client relationship is created by using this website. Laws vary by state and jurisdiction. For advice about your specific situation, consult a licensed attorney in your jurisdiction. mass-torts.com is not a law firm and does not provide legal representation.