Hernandez v. Union Pacific Railroad Company, 8:18-cv-00062

Decedent Saul Hernandez worked for Union Pacific ~1980–1990 as a laborer/trackman; lawsuit alleges occupational exposure to diesel exhaust, asbestos, and silica resulting in gastric (stomach) cancer diagnosed in 2013 and death in 2014.
Decedent had long-term cigarette smoking history and documented Helicobacter pylori infections in 2007 and 2010 (H. pylori is a known cause of gastric cancer).
Plaintiff designated Dr. Robert P. Gale (medical causation expert) and Dr. Joseph R. Landolph (toxicology/general causation expert).
Dr. Landolph relied on population-level data (Canadian railroad study combined with OEHHA default factors and cancer potency figures) and assumed exposure hours to estimate excess cancer risk for a hypothetical worker.
Dr. Gale reviewed literature, relied in part on Dr. Landolph’s report, used Bradford Hill factors, Bayesian methods, and a differential diagnosis; however, he did not review employment records or consider the decedent’s documented H. pylori infections.
The court excluded Landolph’s general-causation opinion (insufficiently tied to gastric cancer) and excluded Gale’s specific-causation opinion (failed to consider H. pylori); because both general and specific causation are required, the court granted summary judgment for the railroad.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Admissibility of Dr. Landolph's general-causation opinion	Landolph shows diesel is a multi-organ carcinogen using peer-reviewed studies and OEHHA methodology	Opinion is impermissibly generalized (estimates risk for all cancers), does not reliably link exposure to gastric cancer	Excluded — unreliably tied to gastric cancer; opinion too broad
Admissibility of Dr. Gale's general-causation opinion	Gale relied on literature and Bradford Hill analysis to opine diesel/silica/asbestos can cause gastric cancer	Lacks exposure-level analysis and relied on Landolph’s broad figures	Not excluded as to general causation (court declines to strike)
Admissibility of Dr. Gale's specific-causation opinion	Differential diagnosis and Bayesian approach support that occupational exposures more likely than not caused decedent's gastric cancer	Gale failed to consider known alternative cause (H. pylori) and lacked occupational exposure data	Excluded — unreliable differential diagnosis because Gale did not consider H. pylori
Summary judgment for defendant	Plaintiff contends FELA’s relaxed causation standard allows jury to find employer played any part in injury	Railroad argues plaintiff lacks admissible expert proof of both general and specific medical causation	Granted — with key experts excluded on causation, plaintiff cannot meet FELA causation burden

Daubert v. Merrell Dow Pharm., 509 U.S. 579 (1993) (trial-court gatekeeping standard for expert testimony)
Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999) (Daubert gatekeeping applies to all expert testimony)
CSX Transp., Inc. v. McBride, 564 U.S. 685 (2011) (FELA uses relaxed causation standard: employer negligence need only play any part)
Bland v. Verizon Wireless, 538 F.3d 893 (8th Cir. 2008) (explaining differential-diagnosis methodology)
Brooks v. Union Pac. R. Co., 620 F.3d 896 (8th Cir. 2010) (medical expert required to prove causation in FELA toxic-tort cases)
Marmo v. Tyson Fresh Meats, 457 F.3d 748 (8th Cir. 2006) (expert testimony unsupported by sufficient facts is inadmissible)
Turner v. Iowa Fire Equip. Co., 229 F.3d 1202 (8th Cir. 2000) (differential diagnosis is admissible when reliably performed)
Guinn v. AstraZeneca Pharm. LP, 602 F.3d 1245 (11th Cir. 2010) (differential diagnosis must consider other plausible causes)
Celotex Corp. v. Catrett, 477 U.S. 317 (1986) (summary-judgment standard)
Anderson v. Liberty Lobby, 477 U.S. 242 (1986) (genuine-issue/material-fact standard for summary judgment)