## Facts

- John Prentis, a parts-department foreman at an automobile dealership, was injured in April 1970 while using a hand-operated (“walkie hi-lo”) forklift manufactured by Yale Manufacturing Co. and sold to his employer in 1952.
- The forklift was a stand-up/walking model operated by lifting a handle; it weighed about 2,000 pounds and was battery-powered.
- With a low battery, the forklift surged while Prentis attempted to start or move it (including on an incline), causing him to lose balance, fall, and fracture his hip.
- Prentis claimed the forklift was defectively designed because it required the operator to stand and lacked a seat, platform, or other adequate support, increasing the likelihood of a fall during surges or jolts.

## Issues

1. In a manufacturer design-defect products-liability case, is it reversible error to refuse separate jury instructions on breach of implied warranty when the jury is properly instructed on negligent design?

## Decision

- The Michigan Supreme Court answered no and reversed the Court of Appeals.
- The Court reinstated the trial court judgment entered on the jury’s verdict of no cause of action for Yale.
- The Court held that, for alleged design defects, negligence and breach of implied warranty require proof of the same elements and are supported by the same evidence; therefore, a separate implied-warranty instruction is not required where negligent-design instructions properly state the governing standard.

## Legal Principles

- In design-defect claims against manufacturers, Michigan treats negligence and breach of implied warranty as essentially the same theory for purposes of proof and jury instruction.
- Design-defect liability is governed by a negligence-based risk–utility test: the question is whether the manufacturer’s choice of design unreasonably exposed users to foreseeable risks in light of the product’s utility and the feasibility of safer alternatives.
- Products-liability doctrines in this setting do not impose strict or absolute liability; the plaintiff must prove a defect (a dangerous condition in the product) and causation.
- When the jury is adequately instructed on negligent design under the risk–utility framework, omission of separate implied-warranty instructions is not prejudicial error.

## Conclusion

Michigan unified negligent-design and implied-warranty theories in manufacturer design-defect litigation and required a negligence-based risk–utility analysis; because the negligence instructions fully covered the operative elements, the failure to give separate implied-warranty instructions did not warrant a new trial.


Prentis v. Yale Mfg. Co., 421 Mich. 670, 365 N.W.2d 176 (Mich. 1984)