Background
Richard Allen DuFour, Jr. worked for nearly three years on shoreline cleanup and boom decontamination in Pascagoula, Mississippi, after the Deepwater Horizon oil spill. He alleged that inhalation and contact exposure to crude oil and chemical dispersants chronically worsened his preexisting asthma.
DuFour sued BP under the Medical Settlement Agreement’s Back-End Litigation Option. To establish causation, he offered opinions from Dr. Michael Freeman and treating physician Dr. Shawn French. The district court declined to hold a live Daubert hearing, excluded both experts’ causation opinions, and granted BP summary judgment.
The Court’s Holding
The Fifth Circuit affirmed. The majority held that general maritime law incorporates the widely accepted toxic-tort requirement that a plaintiff with a non-readily observable injury or an injury having multiple possible causes must offer admissible expert evidence of causation. That framework requires evidence of both general causation—that the substances can cause the alleged harm at relevant exposure levels—and specific causation—that the plaintiff’s exposure caused his injury. The court also confirmed that a district court may exclude unreliable expert evidence at the summary-judgment stage and then enter judgment when the remaining record cannot establish causation.
The district court acted within its discretion by deciding the Daubert motions on the written record, which included expert reports, declarations, and depositions. It also permissibly excluded Dr. Freeman’s opinions because the studies on which he relied did not adequately connect spill-related exposure to worsening preexisting asthma and left too large an analytical gap between the data and his conclusion. Dr. French’s causation opinions were likewise inadmissible because DuFour failed to establish his qualifications to assess the substances at issue or a reliable methodology beyond timing. Without admissible causation evidence, DuFour could not survive summary judgment.
Judge Oldham dissented. He argued that the court could not properly assess whether the expert opinions fit the case without first resolving which substantive law governed causation. He also concluded that the district court unduly discounted a study of more than 24,000 Deepwater Horizon cleanup workers that found a statistically significant relationship between chemical exposure and asthma.
Key Takeaways
- Under Fifth Circuit maritime law, non-readily observable toxic-exposure injuries with multiple possible causes require admissible expert causation evidence.
- A district court need not conduct a live Daubert hearing when the written expert record provides an adequate basis for its reliability determination.
- Studies addressing new asthma or respiratory symptoms do not necessarily establish that exposure worsened a plaintiff’s preexisting asthma.
- Once the causation experts were excluded, summary judgment was proper because DuFour conceded that he could not prove causation without expert testimony.
Why It Matters
The decision reinforces demanding expert-proof requirements for Deepwater Horizon BELO plaintiffs and other maritime toxic-tort claimants. Experts must reliably connect relevant substances, exposure levels, and scientific findings to the plaintiff’s particular condition; temporal association and studies involving materially different populations or outcomes may not suffice.
The divided opinion also highlights an unresolved methodological concern: because Rule 702 asks whether expert evidence fits the facts in issue, the dissent maintained that courts should identify the governing substantive causation law before excluding expert testimony.