Hamilton v. United Parcel Serv., A-17-102

Robert Hamilton, a UPS spotter truck driver, developed progressive cognitive decline and dementia; he claimed chronic workplace carbon monoxide (CO) exposure caused it.
Hamilton sought medical care in October 2012 after headaches and throat irritation; ER carboxyhemoglobin was 2.9% (within the cited normal range). He last worked for UPS in May 2013 and sued in September 2014.
Plaintiffs offered engineering and medical experts (Peter Leiss, Dr. Bianca Marky, Dr. James Madison) alleging spotter-truck exhaust leaks and chronic CO exposure causing neurological injury; Dr. Bansal retracted an earlier causation opinion after learning the 2.9% lab value.
Defense offered industrial hygiene, occupational-health, and neuropsychology experts (Corri Synak, Terry Stentz, Dr. Robert Arias, Douglas Fletcher) who found no air-monitoring or quantitative CO exposure data, identified alternative exposures (welding-related metals), and concluded Alzheimer’s-type disease or insufficient evidence of causation from CO.
The Workers’ Compensation Court found Hamilton had dementia but concluded plaintiff failed to prove chronic, causally significant CO exposure; it found key expert opinions speculative or lacking foundation and dismissed the petition with prejudice.
On appeal, the Nebraska Court of Appeals affirmed, holding the compensation court’s factual findings on causation were not clearly erroneous.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Hamilton proved workplace CO exposure caused or aggravated his dementia	Hamilton: chronic, repetitive low‑level CO exposure at UPS caused or substantially contributed to dementia; expert testimony supports causation	UPS: no quantitative exposure data, single normal carboxyhemoglobin reading, experts’ opinions speculative; alternative nonwork exposures exist	Held for UPS: claimant failed to prove causation by preponderance; factual finding not clearly erroneous
Whether court erred in rejecting Dr. Madison’s causation opinion	Hamilton: exact exposure levels/frequency are often unknowable; expert may rely on reasonable inference and clinical findings	UPS: Dr. Madison lacked foundation—did not know exposure levels or frequency; opinion relied on assumptions	Held for UPS: court permissibly rejected opinion as speculative and lacking adequate factual basis

Potter v. McCulla, 288 Neb. 741 (describes burden to prove injury from employment)
Hintz v. Farmers Co-op Assn., 297 Neb. (explains standard that compensation court findings have force of jury verdict)
Kerkman v. Weidner Williams Roofing Co., 250 Neb. 70 (causation is ordinarily for trier of fact)
Sheridan v. Catering Mgmt., Inc., 252 Neb. 825 (expert must have adequate factual basis; case where limited data still supported causation on these facts)
Riggs v. Gooch Milling & Elevator Co., 173 Neb. 70 (medical evidence can establish compensability from chronic workplace exposures)
Osteen v. A. C. & S., Inc., 209 Neb. 282 (discussion on proving exposure and toxic injury)
Liberty v. Colonial Acres Nursing Home, 240 Neb. 189 (trier of fact decides credibility and weight of expert testimony)