Section 13.28 Product Liability

• Library: Sources of Proof (2014 Ed.)

C. (§13.28) Product Liability

For a plaintiff to recover under a products liability theory for an injury caused by an allegedly defective product, Missouri pattern instructions require that a plaintiff must establish that:

• the defendant sold the product in the course of its business;

• the product “was then in a defective condition unreasonably dangerous when put to a reasonably anticipated use”;

• the product “was used in a manner reasonably anticipated”; and

• the “plaintiff was damaged as a direct result of such defective condition as existed when the” product was sold.

MAI 25.04 [1978 Revision].

While circumstantial evidence may be used to establish inferences supporting these elements, Hale v. Advance Abrasives Co., 520 S.W.2d 656, 658 (Mo. App. W.D. 1975), the inferences must be reasonably probable and must be made “without resorting to guesswork or speculation.” White v. Thomsen Concrete Pump Co., 747 S.W.2d 655, 661 (Mo. App. S.D. 1988); see also Crump v. MacNaught P.T.Y. Ltd., 743 S.W.2d 532, 535 (Mo. App. E.D. 1987) (the court stated that a defect can be inferred if common experience suggests that the accident would not have occurred absent a defect). Expert testimony is crucial in most products liability cases because the cause of accidents and the source of defects are often outside the common experience. For example, an engineer’s testimony identifying the injury-causing defects that made a step van unreasonably dangerous was a crucial element in Asbridge v. General Motors Corp., 797 S.W.2d 775, 778–79 (Mo. App. E.D. 1990). Expert testimony is commonly used to establish insufficient warnings, design defects, manufacturing defects, and the causal relationship between these issues and injury.

An engineering psychologist’s testimony as an expert that a warning label did not sufficiently warn users of dangers was admitted in Tennis v. General Motors Corp., 625 S.W.2d 218 (Mo. App. S.D. 1981). The label was allegedly improper in terms of wording, colors, placement, and similar matters. The qualifications of the expert included design of warning systems and training in how and why people focus their attention on given stimuli and ignore others. Id. at 219. Similarly, a human factors expert was allowed to testify as to how people react to warnings in Cole v. Goodyear Tire & Rubber Co., 967 S.W.2d 176, 185–86 (Mo. App. E.D. 1998).

Expert testimony is also proper to establish a design defect. Landis v. Sumner Mfg. Co., 750 S.W.2d 466...