Products Liability Law Daily Wrap Up, EXPERT EVIDENCE—CHEMICAL PRODUCTS—11th Cir.: Chemical facility owner wins residents’ neurological injury suits after dismissal of causation experts, (Jul 31, 2026)

By Pankhuri Bhatnagar, B.A. LL.B.

The affected individuals failed to show that the subject chemicals were capable of causing their alleged neurological diseases, resulting in the dismissal of their claims.

In an action brought against the owner of a chemical facility by workers and nearby residents who allegedly developed serious illnesses due to the facility’s improper chemical disposal system, the U.S. Court of Appeals for the Eleventh Circuit affirmed the exclusion of the claimants’ general causation experts and summary judgment in favor of the owner. The first challenged expert failed to reliably explain or apply his weight-of-the-evidence methodology and Bradford Hill analysis, while the other merely adopted other experts' opinions and relied on an improper background-risk assessment, warranting judgment for the owner (Davis v. Lockheed Martin Corp., No. 24-10080; DeMilt v. Lockheed Martin Corp., No. 24-10416 (11th Cir. July 28, 2026)).

Background. The consolidated appeals arose from two related toxic tort actions, Davis v. Lockheed Martin and DeMilt v. Lockheed Martin. Several workers and residents brought suit against Lockheed Martin Corporation alleging that the company improperly handled volatile organic compounds at its Sand Lake Road Facility in Orlando, allowing the chemicals to leach into the surrounding soil, groundwater, and air. The claimants contended that exposure to five compounds, trichloroethylene (TCE), perchloroethylene (PCE), toluene, xylene, and styrene, caused them to develop multiple sclerosis, Parkinson's disease, and other neurodegenerative disorders. One claimant also alleged that his wife developed multiple sclerosis and later died after workplace exposure to the chemicals. A district court excluded the claimants’ causation experts under Daubert and subsequently entered summary judgment for Lockheed because the individuals lacked admissible evidence establishing that the chemicals were capable of causing the alleged diseases. This appeal followed.

Legal standard. Toxic tort claims require proof of generation causation (that a substance can cause a given disease) and can be established through three primary methodologies: epidemiological evidence, dose-response relationship, and background risk of disease as per Chapman v. Procter & Gamble Distrib., LLC, 766 F.3d 1296, 1308 (11th Cir. 2014). Epidemiological evidence must be accompanied with facts showing a causal association between the substance and the disease as per In re Deepwater Horizon BELO Cases, 119 F.4th 937, 941 (11th Cir. 2024). Background risk is “the risk a plaintiff and other members of the general public have of suffering the disease or injury that plaintiff alleges without exposure to the drug or chemical in question.” McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1243 (11th Cir. 2005).

Expert evidence. The individuals’ first expert opined that based on the weight of the evidence, the compounds that Lockheed emitted were capable of causing the diseases and injuries suffered by the claimants both individually and in chemical mixtures. The second expert opined that volatile organic compound exposure could have caused the subject illnesses and the zip codes near Lockheed posed a higher risk of mortality from the relevant illnesses than the zip codes farther from Lockheed. The latter opinion was based on the report of a third expert who compared mortality rates in zip codes surrounding the Lockheed facility with mortality rates in Orange County, Florida.

First expert. As noted above, a general caution opinion in epidemiology must reliably assess whether there is an association between a substance and a disease and whether the association is causal. Even assuming that the first essential is fulfilled, the expert did not adequately explain his “weight of the evidence methodology,” which required him to consider alternative explanations and evidence before concluding what the “best explanation” for an association was. Milward v. Acuity Specialty Prods. Grp., 639 F.3d 11, 17–18 (1st Cir. 2011). The expert failed to explain how he selected, evaluated, or weighed the scientific studies supporting his conclusions or how he ruled out competing explanations, rendering his testimony unreliable. Further, he failed to evaluate all Bradford Hill factors with sufficient depth and only addressed a single study despite relying on numerous publications. The Third, Sixth, and Seventh Circuits agree that a failure to do so may constitute a reason to exclude expert testimony. Gilbert v. Lands’ End, Inc., 158 F.4th 839, 851 (7th Cir. 2025). Accordingly, the lower court was within its discretion to exclude his testimony for being unreliable.

Second expert. This expert’s first conclusion that volatile organic compounds could cause the individuals’ neurological diseases merely adopted the opinions of other experts, including the precluded first expert, without independently explaining his own methodology, rendering it an impermissible ipse dixit opinion. Second, his purported background-risk assessment was unreliable because it compared mortality rates between zip codes rather than disease rates among exposed and unexposed populations. Moreover, neither he nor the statistician whose analysis he relied upon established the actual exposure levels of the populations being compared. Accordingly, the Eleventh Circuit upheld the exclusion of the second expert’s evidence as well. Therefore, summary judgment in favor of Lockheed was appropriate in the absence of any admissible evidence on general causation. The court also upheld the district court's certification of the partial judgment in the DeMilt action under Fed. R. Civ. Pro. 54(b), finding no just reason to delay appellate review where both cases presented materially identical issues.

The case is Nos. 24-10080 & 24-10416.

Judge: Brasher, J.

Attorneys: Panagiotis V. Albanis (Morgan & Morgan, PA) for Michael Davis. David B. Weinstein (Greenberg Traurig, PA) for Lockheed Martin Corp.

Companies: Lockheed Martin Corp.

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