37 F.3d 423 (8th Cir. 1994).

One-Sentence Takeaway: To recover on the theory of strict liability for defective design, the plaintiff must prove that he or she was injured as a direct result of defect that existed when product was sold and has the burden to show that product had not been modified to create defect that could have proximately caused the injury.

Summary:  Plaintiff was employed at a business cards company and she was injured when her hand became caught in the moving parts of the printing press.  Plaintiff brought a lawsuit against the manufacturer and distributor of the press based on negligence and strict product liability.  The press had a plastic guard and an electric interlock switch that automatically shut off the press if the guard was opened.  However, the guard was removed, and the interlock switch was disabled, because it saved time and this was a common practice in the printing business.  Plaintiff claimed that she knew this was dangerous but did not want to be fired for using machine correctly.

The trial court granted the Defendants judgment as a matter of law and Plaintiff appealed.

The court of appeal affirmed.  The court reasoned that Plaintiff was required to prove that she was injured as a direct result of a defect that existed when the press was sold.  Plaintiff could not make that showing, however, because the press was modified by a third party after it was sold.

The court held that when a third party’s modification makes a safe product unsafe, the manufacturer and seller is relieved of liability even if the modification is foreseeable.


1. The court in Jones applied Missouri products liability law.  Several jurisdictions disagree with Missouri and the seller in those states is relieved of liability only when post-sale modifications are determined to be unforeseeable.

See, e.g., Anderson v. Nissei ASB Mach. Co., Ltd., 3 P.3d 1088 (Ariz. Ct. App. 1999):

Jones vRyobiLtd. is distinguishable because it relies upon an underlying rule of law that differs from the rule that Arizona has adopted. In Missouri, when a third party’s modification makes a safe product unsafe, the seller is relieved of liability even if the modification is foreseeable.  As stated earlier, in Arizona, only an unforeseeable modification of a product bars recovery from the manufacturer.

2. Misuse of a produce does not constitute alternation of the product.

See, e.g., Bader Farms, Inc. v. Monsanto Co., 2020 WL 6939364 (E.D. Mo. Nov. 25, 2020):

Next, Monsanto argues that third party farmers who misused dicamba was an “alteration of the system” that “when a third party’s modification makes a safe product unsafe, the seller is relieved of liability even if the modification is foreseeable.” Jones v. Ryobi, Ltd., 37 F.3d 423, 425 (8th Cir. 1994). Missouri law does not impose a duty on a manufacturer to “warn[] of unreasonable risks and dangers associated with the use of its product in modified condition.” Hill v. Gen. Motors Corp., 637 S.W.2d 382, 385-86 (Mo. App. 1982) (internal quotation omitted). Nor is a manufacturer required to ensure the safety of the product in a modified condition, even where the manufacturer has affirmative “`knowledge a modification of a given nature would more than likely occur.’ Id. The cases relied upon by Monsanto involve situations where someone altered the product in some way to make it dangerous. In Jones, the plaintiff sued manufacturers of a press she operated at work alleging the removal of the machine’s safety guards had rendered it defective. Jones, 37 F.3d at 425. Here, in contrast, the use of dicamba over the Xtend seed in 2015 and 2016 was not an “alteration” of the product. The product was not used in a modified condition. In other words, misuse of a product is not an alteration of a product. Monsanto’s cases are inapposite.

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