## Facts

- A September 13, 1996 fire severely damaged Jacob and Kathleen Booth’s home; the parties agreed the fire began in the northeast corner of the kitchen.
- Multiple appliances were located in that area, including a dishwasher, a toaster oven, and a microwave.
- The Booths alleged the toaster oven caused the fire; it was manufactured by Black & Decker and purchased about three months before the fire.
- Plaintiffs brought products-liability claims (strict liability, negligence, and breach of warranty) and pursued the action in part as subrogors after insurance payments.
- Plaintiffs relied on an expert, Richard B. Thomas (fire investigator/engineer), who attributed the fire to the toaster oven based on a theory that electrical contacts welded together, leaving the unit energized and overheating.
- Thomas pointed to observed melting and scoring on contacts as support but did not validate the hypothesis through testing or a documented, replicable methodology.
- A fire marshal had identified the microwave as the cause of the fire, creating a competing origin theory.
- The court held hearings to assess the admissibility of Thomas’s opinions under Federal Rule of Evidence 702 and the reliability requirements for expert testimony.

## Issues

1. Whether Thomas’s expert opinions that the toaster oven was defective and caused the fire were admissible under Federal Rule of Evidence 702.
2. If the expert testimony was excluded, whether plaintiffs had sufficient evidence to create a genuine dispute of material fact on defect and causation under specific-defect theories or Pennsylvania’s malfunction theory.

## Decision

- The court excluded Thomas’s expert testimony as unreliable under Rule 702.
- The court held that, without admissible expert testimony, plaintiffs lacked evidence to prove defect and causation.
- The court granted summary judgment for Black & Decker and related defendants on strict liability, negligence, and breach of warranty claims.

## Legal Principles

- Under Rule 702, expert testimony must be both relevant and grounded in a reliable methodology; qualifications alone do not establish admissibility.
- Reliability requires more than a conclusory “bottom-line” opinion; where appropriate, courts assess whether the approach is testable, subject to standards, and capable of objective evaluation.
- In technically complex fire-cause disputes involving multiple plausible ignition sources, a plaintiff generally must present reliable expert evidence to prove causation and defect.
- Pennsylvania’s malfunction theory does not relieve a plaintiff of proving causation; when the causal mechanism is technically complex and alternative causes remain, unsupported inferences are insufficient to reach a jury.

## Conclusion

Because plaintiffs’ causation and defect case depended on expert opinions that lacked a reliable, testable basis and did not adequately address alternative causes, the court excluded the testimony and entered summary judgment for the defendants.


Booth v. Black & Decker, Inc., 166 F. Supp. 2d 215 (E.D. Pa. 2001)