On January 22, 2021, the Fifth Circuit vacated certification of a putative class action against chemical manufacturer Arkema Inc., holding that courts must conduct a full Daubert analysis when expert testimony is relevant to the determination of whether a class can be certified. This ruling brings the Fifth Circuit in line with the Third, Seventh, and Eleventh Circuits.

• Plaintiffs seek to represent a class of some 20,000 property owners within a seven-mile radius of an Arkema facility that released ash and smoke into the community as a result of flooding caused by Hurricane Harvey.
• In granting certification, the district court held that the proposed class could be certified as a damages class under Rule 23(b)(3) because common issues would predominate in the resolution of class claims. The court also certified an injunctive-relief class under Rule 23(b)(2) based on its conclusion that Arkema’s actions applied “broadly to the entire class, and the injunctive relief sought will commonly address this injury.”
• On interlocutory appeal under Rule 23(f), Arkema argued that the district court committed multiple errors, including relying on expert opinions in its certification decision without first ensuring those opinions would be admissible at trial under the Daubert standard. The Fifth Circuit agreed, holding that “the consequential character of class certification” demands that “the Daubert hurdle must be cleared when scientific evidence is relevant to the decision to certify.” According to the court, “if an expert’s opinion would not be admissible at trial, it should not pave the way for certifying a proposed class.”
• In reaching this decision, the court cited similar opinions in the Eleventh and Seventh Circuits, and it specifically echoed the Third Circuit’s reasoning in In re Blood Reagents Antitrust Litigation, 783 F.3d 183 (2015). Quoting from that case, the court explained that “[e]xpert testimony that is insufficiently reliable to satisfy the Daubert standard cannot ‘prove’ that the Rule 23(a) prerequisites have been met ‘in fact,’ nor can it establish ‘through evidentiary proof’ that Rule 23(b) is satisfied.” The court also noted that the Supreme Court previously expressed “doubt” that “Daubert did not apply to expert testimony at the certification stage of class-action proceedings.” See Wal-Mart Stores, Inc. v. Dukes, 564 U.S. 338, 354 (2011).
• Plaintiffs did not challenge the court’s reasoning; instead, they argued that the district court appropriately “applied a full-bore Daubert analysis when it assessed Plaintiffs’ experts.” The Fifth Circuit disagreed, noting that while “[t]he district court did not disregard its gate-keeping role, . . . its analysis of the expert reports reflects hesitation to apply Daubert’s reliability standard with full force.” Accordingly, the court vacated the district court’s order and remanded with instructions to conduct a more searching Daubert inquiry and address other flaws in the class-certification order.
  • In particular, the court emphasized that the district court must meaningfully grapple with Arkema’s arguments that “a trial of class claims would devolve into individualized inquiries on causation, injury, and damages.” It reiterated circuit precedents holding that Rule 23 requires courts to find—not assume—the facts favoring class certification, and that courts must avoid drifting into a “figure-it-out-as-we-go-along” approach.
• This opinion provides an additional basis to challenge class certification and should serve as persuasive authority in circuits where the applicability of Daubert at the class certification stage has not yet been resolved.
• The Fifth Circuit opinion in Prantil v. Arkema Inc., No. 19-20723, is available here.