Background
This appeal is the fourth in a long-running series of cellphone radiation cases stretching back to 2001. The earlier Murray cases — filed by plaintiffs alleging brain tumors caused by cellphone radiation — had been litigated through three prior appeals. In Motorola I (2009) the D.C. Court of Appeals held the claims were not wholly preempted by federal law. In Motorola II (2016), the court sitting en banc abandoned the Frye/Dyas expert admissibility standard and adopted Daubert/Federal Rule of Evidence 702, remanding for further proceedings. In Motorola III (2025), the court upheld the trial court’s exclusion of the Murray plaintiffs’ general causation experts under that new standard, effectively ending those cases.
The Brooks plaintiffs — eighteen separately filed complaints brought by the same counsel as the Murray plaintiffs — were never formally consolidated with the Murray cases until 2023, but beginning in late 2012 they each executed Joint Stipulations agreeing that the trial court’s ruling from the Murray Frye/Dyas hearing on general causation “will apply to this case” and consenting to a stay of their cases until that hearing concluded. General causation was the threshold question of whether cellphone radiation can cause the type of adverse health effects alleged.
After the Murray experts were excluded under Daubert in 2025, the defendant cellphone companies moved for summary judgment against the Brooks plaintiffs on the ground that — bound by the Murray outcome — the Brooks plaintiffs lacked any admissible expert testimony on general causation and therefore could not prove their cases. The trial court agreed and granted summary judgment. The Brooks plaintiffs appealed, arguing they should not be held to the stipulations.
The Court’s Holding
The D.C. Court of Appeals, in a majority opinion by Associate Judge Easterly, affirmed. The court held that the Brooks plaintiffs had agreed — either expressly through their signed Joint Stipulations or implicitly through their counsel’s repeated representations and litigation conduct — to be bound not only by the ultimate substantive result of the Murray expert-admissibility proceedings, but also by all predicate procedural rulings made along the way, including the decisions limiting discovery to general causation and denying the Murray plaintiffs’ requests for additional experts. The court found no basis to declare those agreements nonbinding.
Because the Murray plaintiffs’ general causation experts were deemed inadmissible under Daubert/Rule 702, and because the Brooks plaintiffs had tied their litigation fate to the Murray proceedings, the Brooks plaintiffs were left without the requisite expert testimony to establish general causation. Summary judgment for the cellphone company defendants was therefore proper. Senior Judge Thompson filed a dissenting opinion.
Key Takeaways
- Litigation management stipulations agreeing to be bound by the outcome of a related lead case are enforceable and encompass not just the final ruling but also the procedural rulings predicate to that outcome.
- Plaintiffs represented by the same counsel as a lead-case group cannot escape an adverse result by arguing their later-filed cases should receive a fresh opportunity to conduct discovery or present different experts.
- After more than two decades of litigation, no cellphone radiation plaintiff in the D.C. courts has succeeded in presenting admissible general causation expert testimony under either Frye/Dyas or Daubert/Rule 702.
- Where admissible expert testimony on general causation is a prerequisite to proving a toxic tort claim, the absence of such testimony following exclusion under Daubert supports summary judgment for defendants.
Why It Matters
This decision closes the door on eighteen additional cellphone radiation cases that had been pending — in some instances for over a decade — while the Murray litigation played out. For litigators, the ruling is a clear warning that stipulations tying a case’s fate to a lead-case proceeding will be strictly enforced, including as to discovery limitations and expert substitution restrictions, even when the governing evidentiary standard changes mid-litigation.
More broadly, the decision underscores the durability of Daubert’s reliability gatekeeping in complex causation cases. After the D.C. Court of Appeals replaced Frye/Dyas with Daubert in 2016 and upheld expert exclusion in 2025, this ruling confirms that the same exclusion operates against a coordinated group of related plaintiffs who had agreed to ride along with the Murray vanguard — regardless of how long those cases have been pending or how many claimants are affected.