## Facts

- Michael A. Troja injured himself while operating a Black & Decker radial arm saw, amputating his thumb during a cross-cut.
- Troja borrowed the saw, which originally had been mounted on a metal base with a guide fence.
- To move the saw, Troja and another person removed it from the base and left the base and guide fence behind.
- Troja placed the saw on the floor and created a makeshift guide fence by clamping an aluminum level to the saw.
- While guiding the wood by hand, the saw slipped during the cut and caused the injury.
- The saw’s owner’s manual included operating instructions and safety warnings; Troja’s expert acknowledged the warnings were consistent with then-existing industry standards.
- Troja sued the manufacturer in negligence and strict liability; the negligence count was withdrawn before trial.
- Troja pursued strict liability theories of (1) design defect (no interlock to prevent operation without a proper guide fence) and (2) failure to warn (insufficient warnings about operating without the guide fence).

## Issues

1. Whether the plaintiff presented legally sufficient evidence of a technologically and economically feasible alternative design available at the time of manufacture to submit a design-defect claim to the jury.
2. Whether the trial court properly excluded the plaintiff’s expert opinion on feasibility for lack of adequate foundation and relevant expertise.
3. Whether evidence of later, stronger warnings on similar products was admissible to prove defect or culpable conduct in strict liability.
4. Whether a strict-liability failure-to-warn verdict for the plaintiff can stand absent a finding that the manufacturer knew or should have known of the risk at the time of marketing.

## Decision

- The appellate court affirmed judgment for Black & Decker.
- The directed verdict on design defect was upheld because Troja failed to provide legally sufficient evidence that the proposed interlock/safeguard was technologically and economically feasible when the saw was manufactured.
- The exclusion of the proposed expert feasibility testimony was upheld as within the trial court’s discretion due to inadequate factual and experiential foundation.
- The exclusion of evidence of later warnings was upheld under the rule barring subsequent remedial measures to prove defect or culpable conduct.
- On failure to warn, the jury found the product defective and unreasonably dangerous due to absent “special warnings,” but also found the manufacturer did not know of the defect when it marketed the saw; judgment for the manufacturer followed because knowledge (actual or constructive) at marketing was required.

## Legal Principles

- In a strict-liability design-defect claim, the plaintiff must present non-speculative evidence that a safer alternative design was both technologically possible and economically feasible at the time of manufacture.
- Expert opinion may be excluded where the witness lacks relevant design experience or offers feasibility conclusions unsupported by engineering analysis, data, or other reliable foundation.
- Evidence of subsequent remedial measures, including later-added or strengthened product warnings, is inadmissible to prove defect or culpable conduct in strict-liability product cases.
- Strict-liability failure-to-warn liability requires proof that, at the time of marketing, the manufacturer knew or should have known of the risk that made the warning inadequate.

## Conclusion

The court affirmed a defense judgment in a strict products-liability action involving a radial arm saw, holding that a design-defect theory could not reach the jury without evidence of a technologically and economically feasible safer alternative at the time of manufacture, that speculative expert feasibility testimony could be excluded, that later enhanced warnings were inadmissible as subsequent remedial measures, and that failure-to-warn liability required manufacturer knowledge (actual or constructive) at marketing.


Troja v. Black & Decker Mfg. Co., 62 Md. App. 101, 488 A.2d 516 (Ct. Spec. App. 1985)