Products Liability Law Daily Wrap Up, EXPERT EVIDENCE—HOUSEHOLD PRODUCTS—D. Neb.: Pressure cooker distributor’s expert evidence partly excluded in cooker explosion case, (Nov 12, 2025)

By Pankhuri Bhatnagar, B.A. LL.B.

The distributor’s expert did not have the required medical expertise or research background to diagnose the consumer’s burn injuries or offer opinions based on that diagnosis.

In an action brought against a pressure cooker distributor by a woman who sustained burn injuries when the cooker’s contents exploded onto her, the federal district court in Nebraska granted in part and denied in part her motion to exclude the manufacturer’s expert. The court found that the expert was qualified to opine about the consumer’s hand placement at the time of the explosion based on photographs depicting the location of her burns, his extensive background in biomechanical engineering, his reliance on scientific principles, his peer-reviewed and published study on the trajectory of the expulsed fluids from a cooker, medical records showing an absence of severe burns on the consumer’s forearms, and the lack of protection offered by her clothing (Clary v. Tristar Products, Inc., No. 4:22CV3230 (D. Neb. Nov. 5, 2025)).

Background. In July 2020, a woman was using a Power Quick Pot model Y6D-36 pressure cooker for cooking. After releasing the steam valve and waiting until the steam exited, she twisted the lid open. The lid suddenly blew off and the cooker’s heated contents exploded onto her, resulting in burn injuries to her face, chest, and arms. She brought suit against the product’s marketer and distributor, Tristar Products, Inc., for design defect, negligence, failure to warn, and breach of warranties. The distributor’s expert contradicted the claim that the consumer’s hands were on the lid at the moment of explosion, and the woman sought to exclude these opinions.

Expert evidence. The expert opined that the woman’s testimony and discovery responses were inconsistent with her burns and the product’s testing. He stated two simple scientific facts: (1) burns occur where “hot fluid touches the skin,” and (2) fluid exits a pressure cooker “without passing through the walls or lid of the pressure cooker[.]” Relying on his published study, which tracked the trajectory of water emitting from a pressurized pressure cooker onto a 50th percentile female mannequin, he concluded that the woman’s hands and arms would have been “in the direct path of the broadly escaping contents and should be severely scalded” had her hands actually been on the lid when the explosion occurred. The expert also referred to her medical records statement that she was holding a food steamer that was stuck while her boyfriend was “trying to get a little off.” The records indicated that she had suffered partial-thickness burns to her face, chest, upper breasts, and both inner elbows; but no substantial burns were found on her forearms.

Qualifications. Tristar’s expert held a Ph.D., M.S. and B.S. in Mechanical Engineering, specialized in biomechanics and machine design, had substantial teaching experience in human movement and postural dynamics, had testified as an expert in several cases involving human movement and effort generation, and had participated in numerous joint examinations of pressure cookers. He also published a peer-reviewed study in the Journal of Burns on the trajectory of expulsed contents from a pressurized pressure cooker and its potential for scald injuries. The consumer did not question whether he was qualified to testify as an expert generally, but challenged his expertise to opine about her hands being on the machine’s base at the time of the incident.

Precedent. The woman cited Williams v. Tristar Prods., Inc., 418 F. Supp. 3d 1212 (M.D. Ga. Aug. 27, 2019), an analogous pressure cooker explosion case where the same expert was barred from opining about the plaintiff's arm placement at the time of the explosion. That court found his opinion speculative since the plaintiff had burns on her elbow, in contrast to his observations, and the expert neglected to take into account the impact of her protective clothing on the burn pattern. Likewise, the woman here claimed that she had clear forearm burns and the impact of her clothing on the severity of the burns was not considered. But Tristar countered that Williams did not apply since its expert relied on the woman’s medical records and photographs that showed only forearm redness, which did not medically qualify as “severe burns.” Clothing was immaterial since burns appeared on both her clothed and unclothed areas, establishing that the shirt offered no shielding from scalding. Moreover, the engineer had since published peer-reviewed research directly supporting his fluid-trajectory analysis. In a later court decision, Copeland v. Tristar Prods., Inc., 5:22-CV-00212 (CAR), his similar testimony was upheld based on the study’s publication.

Analysis. The court noted that the expert’s analysis was properly based on (1) two scientific facts about hot fluids and their trajectory; (2) his peer-reviewed scientific study which determined that the trajectory of the expulsed fluids would have contacted the woman’s hands; (3) the University of Nebraska Medical Center’s confirmation that there were no burns to her hands; and (4) the clothing’s lacking of protection. Therefore, he did not rely on inconsistent or incorrect evidence as in Williams, and his knowledge could help a jury understand the evidence and determine how the accident happened. Since his testimony was based on sufficient facts and data and was the result of a reliable methodology, he was qualified to testify about the consumer’s hand placement based on the trajectory of the pressure cooker's expulsed contents and the location of her burns. However, the expert was not a medical professional, his 2020 testing did not establish the severity of burns that would occur in a pressurized explosion, and his biomechanical engineering experience did not enable him to make any burn diagnoses. As such, the court excluded any testimony as to the diagnosis of the woman’s injuries or any opinion based on that diagnosis.

The case is No. 4:22CV3230.

Judge: Bazis, S.

Attorneys: Corey L. Stull (Atwood, Holsten, Brown, Deaver & Spier Law Firm, P.C.) for Dawn M. Clary. Christopher M. Schmidt (Baylor Evnen Wolfe & Tannehill, LLP) for Tristar Products, Inc.

Companies: Tristar Products, Inc.

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