From Motion to Verdict: A Missouri Daubert Hearing and the Diesel Exposure Testimony That Followed
By Paul E. Rosenfeld, M.S., Ph.D., Principal Environmental Chemist, RoseyFields LLC, Santa Monica, California
A challenge decided the day before trial testimony began
In FELA litigation brought by a railroad worker against Canadian Pacific Railway and Soo Line Railroad in Livingston County, Missouri, Dr. Paul E. Rosenfeld, M.S., Ph.D. of RoseyFields LLC faced a Daubert-type admissibility hearing on July 18, 2023, one day before delivering trial testimony on July 19, 2023, a compressed timeline that left no room to adjust methodology between the ruling and the testimony itself (Ralls, 2023).
Missouri’s approach to expert admissibility
Missouri applies its own statutory expert-admissibility standard, codified at Section 490.065 of the Missouri Revised Statutes, which incorporates Daubert-like reliability factors while operating under state procedural rules distinct from the federal Daubert framework, meaning a methodology’s admissibility can turn on jurisdiction-specific statutory language rather than a uniform national standard.
Why railroad diesel exposure reconstruction was the subject of the hearing
As in other FELA matters, the underlying methodology addressed historical diesel exhaust exposure reconstruction for a railroad worker’s career, integrating published emission factors, locomotive technology history, and job-specific activity data to estimate cumulative occupational dose, the same general approach federal courts in Nebraska and Colorado have separately evaluated and admitted (Gillett, 2022; Gonzales, 2023).
The practical significance of surviving a same-week challenge
A same-week sequence from admissibility hearing to trial testimony means the methodology had to withstand scrutiny without the opportunity for further refinement in response to the court’s specific concerns, unlike matters where a Daubert ruling issues months before trial, giving the eventual trial testimony additional evidentiary weight as having survived scrutiny under time pressure.
The Garshick railroad cohort as independent corroboration
As in other diesel exhaust FELA matters, the underlying epidemiological foundation traces substantially to the Garshick railroad worker cohort study documenting elevated lung cancer risk with cumulative diesel exposure, a large, peer-reviewed, non-litigation-driven study that provides independent corroboration for the general causal relationship at issue regardless of the specific jurisdiction’s admissibility standard (Garshick et al., 1988).
IARC’s classification as an independent regulatory anchor
Similarly, IARC’s classification of diesel engine exhaust as carcinogenic to humans (Group 1) provides an independent international scientific body’s conclusion on the general causation question, a fact pattern courts applying state-specific admissibility standards, including Missouri’s, have generally treated as supportive of an expert’s reliance on established toxicological classifications (IARC, Vol 105).
Why emission-factor selection remained central to the challenge
As in the Colorado FELA matters where courts specifically credited Dr. Rosenfeld’s use of published emission factors integrated with worker-activity data, the Missouri challenge similarly turned substantially on whether the specific emission factors applied to the plaintiff’s locomotive fleet and service years were adequately documented and defensible (Gonzales, 2023).
The role of a successful Daubert-type ruling in shaping trial strategy
Once an admissibility challenge is resolved in the plaintiff’s favor, trial counsel can present the full exposure reconstruction methodology to the jury without truncation, whereas an unsuccessful or partially successful challenge may limit which opinions or supporting data the jury ultimately hears, making the outcome of the hearing itself a significant strategic inflection point.
Why state-specific admissibility standards matter to national FELA practice
Because FELA cases are litigated in both state and federal courts across all fifty states, a diesel exposure reconstruction methodology developed once must be capable of satisfying federal Daubert standards, various state-specific statutory equivalents like Missouri’s, and jurisdiction-specific evidentiary rules on expert qualification, a practical reality that shapes how the underlying methodology is documented and presented from the outset.
Why this matter illustrates the full admissibility-to-verdict pipeline
The Missouri Daubert hearing and subsequent trial testimony together illustrate the complete practical pipeline every exposure expert’s methodology must survive: peer-reviewed scientific grounding, jurisdiction-specific evidentiary vetting, and ultimately persuasive presentation to a lay jury, each stage depending on the one before it. Visit RoseyFields.com to read more about Dr. Rosenfeld’s FELA and diesel exhaust exposure assessment work.
References
1. Ralls S, Plaintiff, v Canadian Pacific Railway and Soo Line Railroad, Defendants. Case No. 28LV-CV0020, Circuit Court of Livingston County, Missouri; Daubert hearing July 18, 2023; trial testimony July 19, 2023.
2. Mo Rev Stat § 490.065 (Missouri expert witness admissibility statute).
3. Gillett S v BNSF Railway Co. Case No. 4:20-cv-03120 (D Neb).
4. Gonzales, et al. v BNSF Railway Co. Case No. 1:21-cv-01690 (D Colo).
5. Garshick E, Schenker MB, Munoz A, Segal M, Smith TJ, Woskie SR, Hammond SK, Speizer FE. A retrospective cohort study of lung cancer and diesel exhaust exposure in railroad workers. Am Rev Respir Dis. 1988;137(4):820-825.
6. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. Diesel and Gasoline Engine Exhausts and Some Nitroarenes. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol 105. Lyon, France: International Agency for Research on Cancer; 2014.
7. Federal Employers’ Liability Act, 45 USC §§ 51-60.
8. Rosenfeld PE, Spaeth K, Hallman R, Bressler R, Smith G. Cancer risk and diesel exhaust exposure among railroad workers. Water Air Soil Pollut. 2022;233:171.
9. US Environmental Protection Agency. Health Assessment Document for Diesel Engine Exhaust. Washington, DC: US EPA; 2002.
10. Daubert v Merrell Dow Pharmaceuticals, Inc., 509 US 579 (1993).
11. Federal Rules of Evidence, Rule 702.
12. Rosenfeld PE. RoseyFields LLC: FELA Occupational Exposure Assessment. Santa Monica, CA: RoseyFields LLC; 2026.
13. US Environmental Protection Agency. Revisions to the Guideline on Air Quality Models. 40 CFR Part 51, Appendix W. Fed Regist. 2017;82(10):5182-5235.
14. Mine Safety and Health Administration. Diesel Particulate Matter Exposure of Underground Metal and Nonmetal Miners. 30 CFR § 57.5060. Washington, DC: US Department of Labor.