Products Liability Law Reporter

The Ninth Circuit Court of Appeals held that a plaintiff’s experiments on a spray gun were unsubstantiated and could not form the basis for his expert testimony in a manufacturing defect suit against the spray gun’s maker.

Jason Theis sued Graco, Inc., alleging that a missing check ball in his Probler P2 spray gun led to his injuries and constituted a manufacturing defect. The defendant moved successfully for summary judgment.

Affirming, the Ninth Circuit held that California law requires that causation be established through expert testimony in cases like this one, in which the mechanics, construction, and operation of the product are beyond the common person’s experience. The court noted that even if the plaintiff were qualified as an expert witness, his proffered testimony regarding his independent experiments with the Probler P2 spray gun does not comport with the Daubert standard. The court reasoned that the plaintiff’s experiments are unsubstantiated and undocumented and have not been tested by others. Additionally, the court said, the plaintiff conducted his experiments using an unknown methodology. Therefore, they cannot serve as the basis of his proffered testimony for the trier of fact.

Finding that the plaintiff had offered inadequate causation evidence, the court concluded that summary judgment had been proper.

Citation: Theis v. Graco, Inc., 2019 WL 1281221 (9th Cir. Mar. 18, 2019).