Complete Class Action & Mass Tort Guide

A letter says you may be part of a class action, or an ad asks whether you took a certain drug or had a certain device implanted. If you’re not sure what either means for you, that’s normal.

Here’s the plain answer. A class action is one lawsuit brought for a whole group: when it seeks money, you’re usually included unless you opt out by the deadline in the notice, and bound by the result (Federal Rule of Civil Procedure 23(c)). In a mass tort, people hurt by the same product or event each file their own lawsuit, and federal courts can group those lawsuits before one judge for pretrial work, in a multidistrict litigation, or MDL (28 U.S.C. § 1407). Injury claims often take that route, because injuries differ from person to person.

The hard part usually isn’t the law. It’s the process: a notice sets deadlines you have to meet, an ad can’t tell you whether your case fits, and your own deadline to sue can run while other people’s cases move ahead. Michigan’s rules, current as of September 2026, are in the boxes marked “In Michigan.”

Hurt by a drug, device or product named in a notice or an ad? Get a free case review. Four quick questions, no cost, no obligation.

What’s the difference between a class action, a mass tort and your own lawsuit?

A class action is a lawsuit in which one or more members of a group sue “on behalf of all members” (Federal Rule of Civil Procedure 23(a), or FRCP 23). If the court certifies the class, it appoints lawyers for the whole class, called class counsel (FRCP 23(g)). The core policy, in words the U.S. Supreme Court quoted, is to overcome “the problem that small recoveries do not provide the incentive for any individual to bring a solo action” (Amchem Products, Inc. v. Windsor, 1997).

A mass tort is an act or omission that harms many people, and the cases that follow are “groupings of individual lawsuits alleging the same issues against the same defendant(s)” (Cornell Law School’s Legal Information Institute).

An MDL is a federal procedure, not a kind of claim. When cases sharing “one or more common questions of fact are pending in different districts,” a panel of judges can send them to one court “for coordinated or consolidated pretrial proceedings” (28 U.S.C. § 1407(a)). MDLs “do not have the same commonality requirements as class actions” (committee note to FRCP 16.1, 2025).

Your own personal injury lawsuit is yours alone, and you decide whether to settle (in Michigan, MRPC 1.2(a)). If it’s in federal court and shares questions of fact with the cases in an existing MDL, it can be transferred into that MDL as a “tagalong” action (28 U.S.C. § 1407(a); committee note to FRCP 16.1).

Why are injury cases often handled as mass torts instead of class actions?

Before certifying a class under FRCP 23(b)(3), a court must find that shared questions “predominate over any questions affecting only individual members” and that a class action “is superior to other available methods.” Injuries make that hard. The rule’s 1966 drafters said a “mass accident” injuring many people “is ordinarily not appropriate for a class action,” because questions “not only of damages but of liability and defenses of liability” would likely affect “the individuals in different ways” (committee note, 1966).

In 1997, the U.S. Supreme Court held that a class action meant to settle current and future asbestos claims against 20 companies didn’t meet the federal class-action rules. Quoting the appeals court, it noted that class members “were exposed to different asbestos-containing products, for different amounts of time, in different ways, and over different periods,” and that some had no physical injury while others had lung cancer, disabling asbestosis or mesothelioma. The rule doesn’t “categorically exclude mass tort cases,” the Court said, but the drafters’ warning “continues to call for caution when individual stakes are high and disparities among class members great” (Amchem).

Under a 1994 federal law, an asbestos company reorganizing in bankruptcy can move its asbestos liabilities into a trust that pays present and future claims, and the court can bar lawsuits against the company over those claims (11 U.S.C. § 524(g)). See asbestos and mesothelioma claims.

The same questions come up in toxic exposure lawsuits, chemical exposure claims and food poisoning claims. Workers exposed on the job usually can’t sue their employer, but can often sue a product’s maker (in Michigan, MCL 418.131(1), 418.827(1)); see when you can sue over a work injury.

How does a class action work?

Certification

“At an early practicable time,” the court must decide whether to certify the class (FRCP 23(c)(1)(A)). It must find that the class is too large for everyone to join individually, that there are common questions, and that the representatives’ claims are typical and they will fairly and adequately protect the class (FRCP 23(a)), and, for a Rule 23(b)(3) class, that it passes the predominance and superiority tests above. The order defines the class and appoints class counsel (FRCP 23(c)(1)(B)).

The notice and your choices

For a Rule 23(b)(3) class, the court must direct to class members “the best notice that is practicable under the circumstances,” including individual notice to members who can be identified through reasonable effort. In “plain, easily understood language,” it must explain, among other things, the case, the class, how and when to ask to be excluded, and how a judgment binds members (FRCP 23(c)(2)(B)). Your choices, as the Federal Judicial Center’s model settlement notice puts them:

• Do nothing: you stay in, and the judgment covers you whether or not it favors the class (FRCP 23(c)(3)(B)); so can a settlement the court approves (FRCP 23(e)). Where a claim form is required: “Get no payment. Give up rights.”
• Submit a claim: “The only way to get a payment” when a claim is required.
• Object: tell the court why you don’t like the settlement (FRCP 23(e)(5)), and ask to speak at the hearing on its fairness.
• Opt out: “Get no payment,” but it’s “the only option that allows you to ever be part of any other lawsuit” over the same claims. You keep your own claim and your own deadline.

If you were seriously hurt, talk to a lawyer before the opt-out deadline. The opt-out right covers Rule 23(b)(3) classes; for other classes, such as one seeking only a court order, the rule doesn’t itself provide one (FRCP 23(c)(2)(A)).

Settlement approval and fees

A class’s claims can be settled “only with the court’s approval.” The judge may approve a deal “only after a hearing and only on finding that it is fair, reasonable, and adequate,” weighing whether the class was adequately represented, whether the deal was negotiated at arm’s length, whether the relief is adequate given the costs, risks and delay of trial and appeal and the proposed fees, and whether members are treated equitably relative to each other (FRCP 23(e)(2)). Any member may object, giving specific grounds (FRCP 23(e)(5)(A)). The court also decides class counsel’s fee: it may award “reasonable attorney’s fees,” on a motion announced to class members, who may object (FRCP 23(h)).

Some settlements pay automatically; others need a claim form. In a Federal Trade Commission staff study of 149 consumer class action settlements (September 2019), the median claims rate where a claim was required was 9% of the people sent notice directly.

Hurt by a product named in a class notice? Get a free case review. Four quick questions, no cost, no obligation.

How do MDLs and mass torts work?

Who creates an MDL?

The Judicial Panel on Multidistrict Litigation (JPML), seven federal judges designated by the Chief Justice, transfers cases when that will serve the convenience of parties and witnesses and “promote the just and efficient conduct of such actions” (28 U.S.C. § 1407(a), (d)). It gathers only filed cases: “no authority resides in the MDL Panel to license for consolidated proceedings claims not yet filed” (Amchem). To be in an MDL, you need your own lawsuit on file.

The MDL judge handles pretrial work, from discovery to motions and settlement talks (Federal Judicial Center, 2019). Cases that haven’t ended go back to their original courts by the end of that stage (28 U.S.C. § 1407(a)). The MDL court can’t use the federal venue-transfer law to assign a transferred case to itself for trial (Lexecon Inc. v. Milberg Weiss Bershad Hynes & Lerach, 1998), but can try cases filed in its own district or where the parties waive venue objections (Federal Judicial Center, 2019). Since December 1, 2025, a federal rule says the MDL judge should hold an initial management conference to plan the pretrial work (FRCP 16.1(a)).

How many MDLs are there?

As of September 1, 2026, the JPML listed 166 pending MDLs holding 206,182 pending actions (lawsuits). The 21 MDLs with 1,000 or more pending actions held 94.5% of them, and product liability cases made up 65 of the 166 MDLs, the largest group by type (JPML reports dated September 1, 2026). The Panel updates its list of pending MDLs on the first business day of each month, so you can check whether one exists for a drug or device you’ve seen advertised.

What is a bellwether trial?

“Bellwether trials are individual trials that are conducted by MDL transferee judges with the goal of producing reliable information about other cases centralized in that MDL proceeding,” says a 2019 guide from the Federal Judicial Center and the JPML. Representative ones can show both sides “the strengths and weaknesses of various claims and defenses and the settlement value of cases.” They aren’t appropriate for every MDL, and “in general, bellwether trials do not have a preclusive effect on other cases,” so a bellwether verdict generally doesn’t decide your case. The guide adds that “the vast majority of MDL cases are resolved before ever being remanded for trial.”

How do individual settlements work?

Cases can settle one by one or in groups: bellwether verdicts can supply “the raw data around which to construct a global settlement in the form of a grid-based compensation system” (Federal Judicial Center). Whether to settle remains “a decision to be made by the parties,” and courts can set up ways to compensate the lawyers they appoint to lead the case for their added work, under the “common benefit doctrine” (committee note to FRCP 16.1), so ask how that fits your fee agreement. Before you settle, see who gets paid from your settlement and how injury lawyers get paid.

How long do you have to act?

Every state sets its own deadlines, and an ad doesn’t change yours; see injury deadlines in every state.

A class action can pause the clock. In federal court, filing one “suspends the applicable statute of limitations as to all asserted members of the class” (American Pipe & Construction Co. v. Utah, 1974), and it “remains tolled for all members of the putative class until class certification is denied,” when they may sue on their own or join the case (Crown, Cork & Seal Co. v. Parker, 1983). But the pause “does not permit the maintenance of a follow-on class action past expiration of the statute of limitations” (China Agritech, Inc. v. Resh, 2018). These U.S. Supreme Court decisions involved federal class actions; Michigan’s courts have their own rule (below). An MDL is different: it includes only filed cases, so you need your own lawsuit on file in time (28 U.S.C. § 1407(a)).

How can you tell whether a class action notice is real?

• Look for the court and the case. The Federal Judicial Center’s model notice puts the court’s name at the top and says: “A federal court authorized this notice. This is not a solicitation from a lawyer.”
• Look the case up yourself, not through links or numbers in the message. Federal cases are on PACER, where fees are waived if you spend $30 or less in a quarter; for a state court case, call the clerk of the court named in the notice.
• Compare it with the court file. Judges are advised to approve every form of notice, including what appears on the settlement website, before it goes out (Federal Judicial Center, 2010); for a settlement, that decision is sometimes called preliminary approval (committee note to FRCP 23, 2018). The website, phone number and administrator in your notice should match what the court approved.
• Be careful with requests for money or account numbers until the court’s records confirm the notice.

What should you know before answering a lawsuit ad?

In 2019, Federal Trade Commission staff warned seven legal practitioners and lead generators that some TV ads seeking clients for lawsuits against drug makers may be deceptive or unfair. Some ads, the FTC said, “could leave consumers with the false impression that their physician-prescribed medication has been recalled,” and ads that open with “sensational warnings or alerts” may mislead viewers “into thinking they are watching a government-sanctioned medical alert or public service announcement.”

Don’t stop a prescribed medicine because of an ad. “If you’re thinking about stopping your prescription medications for any reason, talk with your doctor first,” the FTC says. The FDA’s advice: if you stop a medicine or want to use it differently than directed, “consult with your health care professional.”

Check the facts yourself. Search the FDA’s recalls page, though not every recall is posted there, report a side effect through the FDA’s MedWatch program, and check the JPML’s list of pending MDLs.

What to do next

1. Keep taking prescribed medicine unless your doctor says otherwise, get any symptoms checked, and keep every record and bill.
2. Keep the evidence: the notice and its envelope, pharmacy records, device details from your medical records, and the product and packaging if you have them (how to preserve evidence).
3. Check that it’s real on the court’s records or the JPML’s list.
4. Write down every date: the opt-out, objection and claim deadlines, any fairness hearing, and your own deadline to sue.
5. Get a free case review before the first deadline. A lawyer can tell you whether your claim fits a class, an MDL or a lawsuit of your own; get any fee agreement in writing. Get a free case review, or, if you were hurt in Michigan, compare Michigan injury lawyers.

What waiting can cost

• Your choices in a class. A judgment or approved settlement binds members who didn’t opt out in time (FRCP 23(c)(3), (e); MCR 3.501(D)(5)).
• Your right to sue. In Michigan, generally 3 years (MCL 600.5805(2), (12)), and a pause from a class action ends on set events, such as opting out (MCR 3.501(F)(2)).
• A place in an MDL. It gathers only cases already filed (28 U.S.C. § 1407(a)).

What a good outcome looks like

You know whether you’re in a class and what staying in or opting out would mean. If you were hurt, your claim is filed on time and valued on your own injury and losses, and any settlement is your decision, with its terms and the fee in writing. From wondering what a letter or an ad means for you to knowing which kind of case fits, what each choice would cost you and how long you have to act.

For more on defective products, drugs and toxic exposure, browse the defective product and toxic exposure guides, or see how product liability claims work.

Updated September 28, 2026

This guide is general information, not legal advice, and laws change. For advice about your situation, talk to a lawyer licensed in your state. Reading this page or contacting us does not create an attorney-client relationship.