149 F.4th 408
4th Cir.2025Background
- Lee Ann Sommerville, representing a class, sued Union Carbide Corporation and Covestro LLC over alleged exposure to ethylene oxide (EtO), a carcinogenic gas emitted by their plant in South Charleston, WV.
- Sommerville claimed the EtO emissions increased her (and class members') risk of disease, requiring medical monitoring covered by the plant owners.
- The district court excluded Sommerville's expert (Dr. Sahu) and granted summary judgment for defendants, holding Sommerville lacked Article III standing due to no manifest physical injury.
- The district court also found Sommerville's expert testimony unreliable under Daubert and Rule 702, focusing on the expert's modeling inputs and assumptions.
- On appeal, the Fourth Circuit reversed, holding Sommerville had standing under federal law and that the district court erred in excluding Dr. Sahu's testimony.
- There was a dissent arguing that costs of medical monitoring alone do not confer Article III standing for damages claims absent imminent harm.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Article III Standing for Medical Monitoring Claims | Exposure to EtO and present need/cost for monitoring are concrete injuries under WV law and satisfy Article III | Actual, concrete harm required; future risk/monitoring cost is too speculative without manifest injury | Plaintiffs alleging elements of WV medical monitoring tort have standing; exposure plus medical necessity is sufficient |
| Exclusion of Dr. Sahu’s Expert Testimony | Dr. Sahu’s method and use of data are reasonable and go to weight, not admissibility | Dr. Sahu’s assumptions and data inputs unreliable, so testimony should be excluded | Excluding expert based on disagreement over data/witness credibility is error; testimony should be admitted |
| District Court’s Summary Judgment | Summary judgment improper without admissible expert testimony being considered | Without admissible expert proof, no evidence of exposure, so summary judgment proper | Reversed summary judgment; Dr. Sahu’s testimony admissible and creates issue of fact |
| Applicability of Beck v. McDonald (speculative harm) | Present need for monitoring creates concrete injury, unlike speculative future harms | Monitoring costs arise from speculative, not impending, risk (cancer), so not injury in fact | Beck inapplicable; exposure and required monitoring are not speculative but present and concrete injuries |
Key Cases Cited
- Bower v. Westinghouse Elec. Corp., 522 S.E.2d 424 (W. Va. 1999) (Recognized common law medical monitoring claims in WV—exposure plus medical necessity is actionable)
- Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993) (Set standards for admission of expert testimony—must be reliable and relevant)
- Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999) (Daubert applies to technical and other specialized knowledge, not just science)
- TransUnion LLC v. Ramirez, 594 U.S. 413 (2021) (Discussed concrete harm and Article III standing—damages claims require present injury, not just risk of future harm)
- Beck v. McDonald, 848 F.3d 262 (4th Cir. 2017) (Costs incurred in response to speculative threat insufficient for Article III standing)