Key Points

  • The Fifth Circuit held 2-1 that general maritime law incorporates the toxic-tort causation framework requiring expert proof of general and specific causation for non-readily observable injuries.
  • The majority, by Judge Priscilla Richman, expressly agreed with the holding of the unpublished 2009 decision Seaman v. Seacor Marine L.L.C.
  • The court held that, in the correct procedural posture, district courts should apply Daubert to disqualify experts at summary judgment.
  • The panel found no abuse of discretion in deciding the Daubert motions without a hearing or in excluding Drs. Michael Freeman and Shawn French, and affirmed summary judgment for BP.
  • Judge Andrew S. Oldham dissented, arguing that Rule 702 fit depends on the governing substantive law, which no one had identified, and that the Lawrence Study's dose-response trend should have reached a jury.

A divided federal appeals court on Oct. 27 upheld a judgment for BP against a Deepwater Horizon cleanup worker who blamed the 2010 oil spill for worsening his asthma. The court ruled that general maritime law requires expert proof of causation for injuries that jurors cannot assess from everyday experience.

Judge Priscilla Richman wrote for the U.S. Court of Appeals for the Fifth Circuit, joined by Judge Ramirez. The majority affirmed a Mississippi federal judge's decision to exclude both of Richard Allen DuFour Jr.'s causation experts without a live hearing and to grant summary judgment in BP's favor. Judge Andrew S. Oldham dissented.

The majority expressly agreed with the holding of Seaman v. Seacor Marine L.L.C., an unpublished 2009 Fifth Circuit decision. Under that rule, expert testimony is required to establish causation in a toxic-tort case. The court also held that judges may use Daubert, the Supreme Court's 1993 standard under which, the majority wrote, trial judges must determine whether expert testimony "is both reliable and relevant," to disqualify experts at summary judgment.

DuFour worked for almost three years in Pascagoula, Mississippi, on shoreline cleanup and boom decontamination, according to the opinion. He alleged that crude oil and chemical dispersants he inhaled and touched caused chronic worsening of his asthma. He sued under the Back-End Litigation Option, a provision of the Medical Settlement Agreement in the Deepwater Horizon class action. A plaintiff suing under that option must prove, among other things, that his injuries were "legally caused by" exposure to substances during response efforts.

DuFour and BP both told the court that maritime law governed. Richman wrote that Seaman "although unpublished, was well-reasoned and clearly in line with decisions in our circuit and in other circuits that have applied maritime law." She cited decisions of the Second and Eleventh Circuits and wrote that DuFour's claims "are among the class of non-readily observable injuries, or those with multiple possible etiologies, that traditionally require an expert to survive summary judgment on legal causation."

The majority relied on the Supreme Court's 2024 decision in Great Lakes Insurance SE v. Raiders Retreat Realty Co., in which the Court explained that "federal courts possess authority to create and apply maritime law." Richman wrote that either a body of decisions had already established the causation rule or that the Fifth, Second and Eleventh Circuits had created it.

On timing, the majority tied the Daubert ruling to the district court's scheduling order, which set deadlines for expert designations and dispositive motions. "Provided that the case is in the correct procedural posture, courts should apply Daubert to disqualify experts at the summary judgment stage of a proceeding," Richman wrote. She noted that DuFour never argued that more time would let him present different expert evidence, "So, his claim rises or falls on the record presently before us."

The panel held that the district court acted within its discretion in deciding the motions on the papers. That court had found that "neither a hearing nor oral argument would be helpful or otherwise warranted," given the thoroughness of the parties' briefs and exhibits and its familiarity with the issues. The panel added that the record included depositions, declarations and reports from the relevant experts.

The central dispute concerned Dr. Michael Freeman's reliance on the Lawrence Study, a study of Deepwater Horizon cleanup workers. The study excluded workers who reported an asthma diagnosis before the April 20, 2010, disaster, and DuFour had suffered from asthma since childhood. When self-reported wheezing was removed from the study's definition of asthma, its results were "largely attenuated." The district court found "too great of an analytical gap between the data and the conclusions" in Freeman's report.

Richman wrote that the study tracked exposed workers' risk of developing asthma rather than the severity of asthma they already had. She rejected the dissent's reliance on the study's statistical significance, writing that statistical significance "is only a useful metric insofar as the underlying results of the Study capture a meaningful relationship between relevant variables."

The panel also upheld the exclusion of Dr. Shawn French, a treating pulmonologist who offered his causation opinion in a deposition rather than a written report. The district court found that French lacked qualifications on the effects of the substances at issue and relied on "temporal connection alone." The majority affirmed on those grounds and expressly declined to decide whether treating physicians must file expert reports for opinions formed for litigation, a question it called unsettled.

Oldham opened his dissent by writing that he was "unconvinced that Richard Allen DuFour, Jr., should be poured out of court." He argued that the fit Daubert demands between expert testimony and the facts in issue depends on the substantive law governing the claim. "We cannot uphold the district court's Daubert ruling without first identifying the relevant substantive law," he wrote. He illustrated the point with a hypothetical plaintiff bitten by spiders in two states with different causation rules.

On the question of which law governed DuFour's suit, Oldham wrote, "We do not know." He said the settlement's choice-of-law clause covers only interpretation of the agreement and release, and that the parties' agreement on governing law did not bind the court.

Oldham called the study's linear dose-response trend a basis for a jury to infer aggravation. "That slices the salami far too thin," he wrote of the majority's distinction between incidence and severity. "If X demonstrably and linearly causes Y, then a factfinder could reasonably find that X exacerbates Y." He described the Federal Judicial Center's Reference Manual on Scientific Evidence as "biased and scandal-ridden," citing a letter from 27 state attorneys general.

The majority responded in a footnote that the passage it quoted was "very similar to language in the uncontroversial third edition of the Reference Manual." Oldham wrote that striking Freeman's report as ipse dixit "makes as much sense as striking the report for using a disfavored font."

The Fifth Circuit affirmed, leaving in place the summary judgment for BP in the Southern District of Mississippi case, No. 1:19-CV-591.