Michael Davis v. Lockheed Martin Corporation

Court of Appeals for the Eleventh Circuit·Decided July 28, 2026·No. 24-10080·Published

Opinion

USCA11 Case: 24-10080 Document: 51-1 Date Filed: 07/28/2026 Page: 1 of 21

FOR PUBLICATION

In the

United States Court of Appeals For the Eleventh Circuit

No. 24-10080

MICHAEL DAVIS, on behalf of himself and as personal representative of Carol Davis, Plaintiff-Appellant,

THE ESTATE OF CAROL DAVIS, Plaintiff,

versus

LOCKHEED MARTIN CORPORATION, Defendant-Appellee.

Appeals from the United States District Court for the Middle District of Florida D.C. Docket No. 6:22-cv-00081-RBD-DCI

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2 Opinion of the Court 24-10080

No. 24-10416

VERVICIA HENDERSON, on behalf of herself and as personal representative of Craig Henderson, et al., Plaintiffs,

DONNA DEMILT, ERIC RUTLEDGE, EMILIO SAN MARTIN, BRIAN SLUSARZ, MICHAEL MCGARRY, et al., Plaintiffs-Appellants,

versus

LOCKHEED MARTIN CORPORATION, UNIVERSAL CITY PROPERTY MANAGEMENT III, LLC, Defendants-Appellees,

NBCUNIVERSAL MEDIA, LLC, et al., Defendants.

Appeals from the United States District Court for the Middle District of Florida D.C. Docket No. 6:21-cv-01363-RBD-DCI

Before JILL PRYOR, LUCK, and BRASHER, Circuit Judges. BRASHER, Circuit Judge:

24-10080 Opinion of the Court 3

This appeal arises from two cases alleging that Lockheed Martin permitted toxic waste to leach into the area surrounding its manufacturing facility, inflicting neurological harm on workers and nearby residents. The plaintiffs submitted testimony from two experts to prove that the toxic waste could have caused their neurological conditions. In response, Lockheed Martin moved to exclude the experts as unreliable and moved for summary judgment based on a lack of general causation evidence. The district court granted Lockheed’s motions to exclude, explaining that one expert had not reliably explained or applied his “weight of the evidence” methodology and that the second expert relied on the first expert’s report. The court then granted Lockheed’s motions for summary judgment, explaining that the plaintiffs lacked reliable general causation testimony.

The question in this appeal is whether the district court abused its discretion when it excluded these two experts as unreliable and granted summary judgment based on this exclusion. Because the experts did not reliably apply their methodologies and without those experts the plaintiffs lacked general causation evidence , the district court did not abuse its discretion in determining that their testimony was unreliable and granting summary judgment . Accordingly, we affirm.

I.

This appeal comes to us from decisions in two related district court cases: Davis v. Lockheed Martin and DeMilt v. Lockheed Martin. Because the cases are based on substantially the same

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claims, the same district judge managed and coordinated discovery in both. He also entered essentially the same order on review in both cases.

The plaintiffs allege that Lockheed Martin 1 mishandled toxins , called volatile organic compounds, at its Sand Lake Road Facility in Orlando. The DeMilt plaintiffs are a subset of a larger group of plaintiffs who allege that these compounds leached into the surrounding soil, groundwater, and air, causing them or their close relatives to develop serious health conditions. The DeMilt plaintiffs allege that these compounds caused their multiple sclerosis, Parkinson ’s, or other neurodegenerative diseases. Similarly, Davis alleges that his wife was exposed to these compounds while she worked for Lockheed, and that this exposure caused her to develop multiple sclerosis and pass away. Collectively, the appellants say that five compounds caused their injuries: TCE, PCE, toluene, xylene , and styrene.

Toxic tort claims like these ordinarily require a plaintiff to prove general causation—that a substance can cause a given disease . RESTATEMENT (THIRD) OF TORTS: LIAB. FOR PHYSICAL AND EMOTIONAL HARM § 28 cmt. c(3) (A.L.I. 2010). Experts establish

1 The plaintiffs in DeMilt also sued Universal City Property Management, al-

leging that the company had engaged in a joint venture with Lockheed to contaminate the area. The addition of this defendant in DeMilt does not meaningfully change our analysis, so for brevity, we refer only to Lockheed in the remainder of this opinion.

24-10080 Opinion of the Court 5

general causation through three primary methodologies: epidemiological evidence, dose-response relationship, and background risk of disease. Chapman v. Procter & Gamble Distrib., LLC, 766 F.3d 1296, 1308 (11th Cir. 2014).

Experts who use epidemiological evidence to establish general causation must show that there is an association between a substance and a disease and that the association is causal. See In re Deepwater Horizon BELO Cases, 119 F.4th 937, 941 (11th Cir. 2024) (citing Michael D. Green et al., Reference Guide on Epidemiology, in REFERENCE MANUAL ON SCIENTIFIC EVIDENCE 549, 554, 597 (Fed. Jud. Ctr., 3d ed. 2011)). Because it is difficult to conclusively prove causation in epidemiology, experts often use a methodology called the “weight of the evidence” methodology, by which they infer the best explanation for an association. See In re Zoloft (Sertraline Hydrochloride ) Prods. Liab. Litig., 858 F.3d 787, 795 (3rd Cir. 2017). Either as part of the weight of the evidence methodology or as part of a separate methodology, experts can also evaluate the strength of associations they find by using nine metrics called the Bradford Hill factors. See Green, supra, at 599–600.

The plaintiffs’ two general causation experts applied a mix of these methodologies. Dr. Daniel Kantor applied an epidemiological evidence approach. And Dr. Ronald Kendall applied both an epidemiological evidence approach and a background risk approach . Dr. Charles Cowan provided a statistical analysis that informed Kendall’s background risk approach.

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Kantor’s opinion stated that “[b]ased on the weight of the evidence,” the compounds that Lockheed emitted, “both individually and in chemical mixtures, are capable of causing the diseases and injuries that have been suffered by Plaintiffs.” Doc. 58-1 at 29 (Davis); Doc. 138-1 at 29 (DeMilt). Lockheed filed rebuttal reports asserting that Kantor failed to explain his methodology and failed to evaluate the Bradford Hill factors. In response, Kantor described the search criteria he used to find studies and stated that his review “did in fact satisfy the Bradford Hill criteria.” Doc. 58-2 at 3–4 (Davis ); Doc. 138-2 at 3–4 (DeMilt). He also briefly explained how he might apply the Bradford Hill criteria to one of the studies that he cited. Id. at 7.

Kendall’s expert opinion stated that he had reviewed other experts’ reports, including Kantor’s and Cowan’s, and concluded that: (1) volatile organic compound exposure could have caused the plaintiffs’ illnesses; and (2) the zip codes near Lockheed posed a higher risk of mortality from the plaintiffs’ illnesses than the zip codes farther from Lockheed. The relevant part of Cowan’s expert opinion compared mortality rates in zip codes surrounding the Lockheed facility with mortality rates in Orange County, Florida. He found statistically significant results showing that the Lockheed zip code had higher mortality rates related to “Diseases of Central Nervous System” and Parkinson’s.

Lockheed moved to exclude the expert opinions of Kantor and Kendall and moved for summary judgment based on a failure to establish general causation.

24-10080 Opinion of the Court 7

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