Potter v. Chicago Pneumatic Tool Co.
694 A.2d 1319 (Conn. 1997)


  • The plaintiffs were employed as “grinders,” positions which required use of pneumatic hand tools to smooth welds and metal surfaces.
  • The plaintiffs used the tools, manufactured by the defendant, for approximately twenty-five years.
  • They eventually suffered from permanent vascular and neurological impairment of their hands – i.e., “hand arm vibration syndrome.”
  • Suit was brought, alleging that the tools were defectively designed because they exposed the plaintiffs to excessive vibration.
  • D argued that P had to show the existence of a feasible alternative design and urged the court to abandon the consumer expectation test for the risk-utility test.

After a six week trial, the trial court rendered judgment on jury verdicts in favor of the plaintiffs, finding that the defendants’ tools had been defectively designed so as to render them unreasonably dangerous.

Whether plaintiffs were required to prove that there was a feasible alternative design available at the time that the defendants put their tools into the stream of commerce.

No. Affirmed.


  • In rejecting the pure risk-utility approach, the court felt that the feasible alternative design requirement imposed an undue burden on plaintiffs that might preclude otherwise valid claims from jury consideration.
    • Such a rule would require plaintiffs to retain an expert witness even in cases in which lay jurors can infer a design defect from circumstantial evidence.
  • However, the court noted that there will be some instances involving complex product designs in which the ordinary consumer may not be able to form expectations of safety.
    • In those cases, risk-utility may be taken into consideration.
  • Thus, the court adopted a modified consumer expectation test.
    • The modified consumer expectation test provides the jury with the product’s risks and utility, and then inquires whether a reasonable consumer would consider the product unreasonably dangerous.
  • Here, “because there was sufficient evidence as a matter of law to support the determination that the tools were unreasonably dangerous based on the ordinary consumer expectation test, we conclude that this instruction was appropriately given to the jury.”
  • A few other states have also embraced the consumer expectations test as the primary/exclusive test for defective design.
    • However, the Restatement disagrees and rejects it as the stand-alone test.

Rule: The consumer expectations test applies generally to determine design defect, but in special, complex instances, the modified consumer expectations test (in which risk and utility are balanced) may be necessary.