## Facts

- David W. Thibault bought a Craftsman rotary power lawn mower from Sears in 1968 and had over fifteen years’ experience using similar mowers.
- The mower housing bore a warning: “Keep Hands & Feet From Under Mower.”
- The instruction booklet advised twice to mow slopes lengthwise rather than up and down.
- Thibault chose to mow a steep slope up and down, lost his balance, and fell while gripping the mower handle.
- His foot ended up under the mower housing and was injured by the blade.
- Thibault claimed the injury occurred because the mower lacked a rear trailing guard that would have prevented his foot from entering the blade area.
- Sears disputed causation, asserting Thibault lifted the mower while falling, bringing the blade onto his foot, and argued Thibault’s conduct violated explicit operating instructions.

## Issues

1. Whether strict products liability requires proof that the product was in a defective condition unreasonably dangerous to the user and that the defect caused the injury, rather than operating as insurer-like loss shifting.
2. Whether the mower’s design, including the absence of a rear trailing guard, rendered it unreasonably dangerous under a design-defect risk–utility analysis, considering warnings and feasible alternatives.
3. Whether the plaintiff’s misuse or other misconduct may be considered in strict liability and, under comparative fault principles, bar recovery when the plaintiff’s responsibility exceeds 50%.
4. What role warnings and evidence of industry standards play in determining defect and unreasonable danger.

## Decision

- The New Hampshire Supreme Court affirmed judgment for Sears after a jury returned verdicts for Sears on negligence and strict liability.
- The court held that strict liability does not impose absolute liability; the plaintiff must prove a defective condition unreasonably dangerous and causation.
- The evidence permitted the jury to find either that the mower was not unreasonably dangerous, that the alleged design defect did not cause the injury, or that plaintiff misconduct was the predominant cause and barred recovery under the state’s comparative fault rule.
- The court treated conflicts in testimony about accident mechanics and the utility of a trailing guard as jury questions on defect and causation.

## Legal Principles

- Strict products liability requires proof that the product left the seller in a defective condition unreasonably dangerous to the user or consumer, and that the defect was a legal cause of the injury.
- Design-defect liability is assessed by balancing product utility against risk, including feasibility of safer design, effect on cost, and effect on product function (risk–utility).
- Warnings and instructions are relevant to whether a product is unreasonably dangerous and may support a finding of no defect when adequate in light of foreseeable use.
- Plaintiff misconduct, including misuse or abnormal use, may be considered in strict liability; comparative fault principles may reduce or bar recovery when the plaintiff’s fault exceeds the applicable threshold.
- Compliance with industry standards is relevant evidence but not dispositive on defect or unreasonable danger.

## Conclusion

The court sustained a defense verdict where the jury could reasonably find no unreasonably dangerous defect or no causation, and could also attribute predominant responsibility to the plaintiff’s instruction-contrary use under comparative fault principles applicable to strict liability.


Thibault v. Sears, Roebuck & Co., 395 A.2d 843 (N.H. 1978)