A prominent legal organization released a report on Thursday finding that products liability lawsuits are behind the growth of multidistrict litigation, which many in the defense bar contend needs new rules to fix a host of procedural problems.

According to the report by Lawyers for Civil Justice, about 90 percent of all cases in multidistrict litigation for the past 25 years have been in products liability, as opposed to antitrust, patent infringement or other litigation. The Arlington, Virginia-based group based its report on records at U.S. courts and the U.S. Judicial Panel on Multidistrict Litigation through Sept. 30, 2017.

The report, called “Rules 4 MDLs: Calculating the Case,” comes as Lawyers for Civil Justice and others in the defense bar are pushing for changes to MDLs that would stem several procedural problems, such as the filing of meritless cases and the use of outside litigation financing.

“The problems with the existing rules happen more frequently in these kinds of cases, these product cases,” said Alex Dahl, general counsel to Lawyers for Civil Justice. “And so, the fact that those are the ones in most of the MDL cases shows the extent of the problem.”

The report’s findings refute arguments from the American Association for Justice, the nation’s largest plaintiffs’ bar organization, that MDLs are too diverse to have their own rules under the Federal Rules of Civil Procedure.

“Anti-consumer groups want to undermine MDLs because they know that MDLs are an effective tool for holding big corporations accountable,” said AAJ spokesman Peter Knudsen in an email. “MDLs ensure the complex litigation is handled efficiently and fairly. LCJ’s proposal would create a one-sided set of rules for all MDLs, but judges should have the discretion to determine how best to manage cases in their courtroom.”

A subcommittee of the Advisory Committee on Civil Rules is looking into whether to establish MDL rules, particularly relating to outside litigation financing, which defense bar groups have insisted is behind the surge in caseload.

The civil rules committee agreed to take up MDL matters last November, after the U.S. Chamber of Commerce’s Institute for Legal Reform, Lawyers for Civil Justice and other business groups submitted a proposal that would amend Federal Rule of Civil Procedure 26 to require disclosure of all outside financing agreements that are contingent on the outcome of a case.

On Sept. 14, Lawyers for Civil Justice submitted a list of proposed rules to the civil rules committee. Absent a set of rules, judges will continue to issue conflicting rulings on key decisions in the cases, Dahl said.

“Rule 1 of the Federal Rules of Civil Procedure says the rules should apply to all cases in the federal courts,” he said. “But it is well understood in the MDL context that the rules are not applied uniformly or evenly, or even at all in some matters. Our view is that one of the reasons for that is the rules were written before MDLs were created and in certain ways aren’t pragmatic for handling these big cases with thousands of parties involved.”

And they are big cases. Cases that get coordinated into MDLs make up 47 percent of the total civil docket of 266,108 cases in U.S. courts, when excluding Social Security and prisoner lawsuits, according to Lawyers for Civil Justice’s report. The number of cases have more than tripled since 1992, when litigation over breast implants and asbestos exploded.

Dahl said MDL dockets are getting bigger because many of the plaintiffs’ cases haven’t been adequately vetted. Lawyers for Civil Justice has proposed that plaintiffs submit detailed documentation of the product and injury alleged within 60 days of filing a case. It also suggested that plaintiffs disclose outside litigation financiers to the court and to defendants, and that MDLs should have a rule encouraging interlocutory appeal of key issues like pre-emption and expert evidence.