Fashioning Justice: Lack of Expert Testimony Unravels Defective Uniform Case

In 2015 American Airlines (“American”) ordered new uniforms for its pilots, flight attendants, and customer service agents to wear. American contracted with Twin Hill Acquisition Company, Inc. (“Twin Hill”) to provide American with the new uniforms. American employees alleged that the new uniforms contained harmful chemicals that caused rashes, hives, headaches, and throat swelling. Plaintiffs filed suit alleging American engaged in battery and intentional infliction of emotional distress and suit against Twin Hill under strict and negligent products liability.

On April 11, 2025, the District Court for the Northern District of Illinois took up the defendants’ motion for summary judgment based on the plaintiffs’ two experts’ failure to use reasonable methodologies to establish a causal link between the uniforms made by Twin Hill and the harm alleged by the plaintiffs.

The defendants also filed Daubert motions along with the Motion for Summary Judgment to disqualify the plaintiffs’ expert witnesses. The Court ruled in favor of the defendants on their Daubert motion by disqualifying the plaintiffs’ expert reports for lacking reliable testimony. The Court recited Rule 702 of the Federal Rules of Evidence states that a party seeking to introduce expert testimony must first establish by a preponderance of the evidence that “the expert’s scientific, technical, or other specialized knowledge will help the trier of fact,” “the testimony is based on sufficient facts or data,” “the testimony is the product of reliable principles and methods,” and “the expert’s opinion reflects a reliable application of the principles and methods to the facts of the case.”

The Court used the Daubert threshold to state that both of the plaintiffs’ experts failed to connect a “biologically plausible theory” for how the plaintiffs’ negative reactions to the uniforms could be related to chemical exposure.

Because the plaintiffs’ toxicologist expert failed to provide a plausible biological theory of exposure, and because any such theory would not have been tested, peer reviewed, or scientifically accepted, the expert’s methodological basis for his causation opinion was insufficiently reliable to be admitted under the Daubert standard and Federal Rule 702.

The plaintiffs maintained that their experts did not need such a theory because one of the experts was able to infer the causal relationship between the symptoms and Twin Hill uniforms by applying the Bradford Hill methodology by using the complaints submitted by American’s employees.

The Bradford Hill criteria is a well-established methodology for showing that correlation between two variables is representative of a causal relationship. It involves first determining whether a statistically significant association exists between two phenomena and then analyzing that association along nine criteria: strength of association, consistency, specificity, temporality, biological gradient, plausibility, coherence, experiment, and analogy.

The court reasoned that the plaintiffs’ experts failed to show any statistical association between the exposure to the uniforms and the plaintiffs’ alleged ailments. The experts failed to cite any epidemiological or toxicological study linking the uniforms, or any of the chemicals they contained, to any type of adverse reaction. The plaintiffs’ experts attempt to identify an association also suffered from a related but deeper flaw: the complaints drawn upon were not a reliable indicator of the rate of symptomology among even the exposed treatment group. The court reasoned that the complaint volume alone only revealed the rate at which American employees filed complaints, not an association to a design defect in the uniforms and adverse reactions.

The methodological basis for the plaintiffs’ expert testimony was deemed insufficiently reliable to be admitted under Rule 702. The misapplication of the Bradford Hill framework further underscored the methodological unsoundness of the plaintiffs’ experts’ approach. The decision to ignore alternative explanations for the plaintiffs’ symptoms—explanations made plausible by substantial supporting evidence in the record—provided an independent basis to exclude any of the plaintiffs’ experts’ testimony.

Practical Considerations: