O’Brien v. Muskin Corp.
463 A.2d 298 (N.J. 1983)


  • O’Brien was injured when he dove into an above-ground pool. His outstretched hands hit the vinyl-lined pool and slid apart, and his head hit the bottom.
  • “DO NOT DIVE” was written in ½ inch letters just below the logo.
  • He sued, alleging that the pool was defectively designed and bore an inadequate warning.
  • One of his experts testified that the pool should’ve been lined with rubber latex instead of vinyl, which is twice as slippery.
  • He admitted, however, that he didn’t know of any above-ground pools lined with a material other than vinyl.


  • The trial court refused to charge the jury on design defect and only submitted the issue of the warning.
    • The jury found O’Brien 85% negligent, thus under NJ law, he was barred from recovery.
  • The Appellate Division reversed.

Did the trial court err in refusing to submit the design defect issue to the jury?

Yes. Appellate Division affirmed.


  • “Risk-utility analysis” based on a comparison of utility of product with risk of injury that it poses to public is appropriate when product may function satisfactorily under one set of circumstances, yet because of its design present undue risk of injury to user in another situation.
    • “The assessment of the utility of a design involves the consideration of available alternatives.”
    • “The evaluation of the utility of a product also involves the relative need for that product; some products are essentials, while others are luxuries.”
    • Some products, including some for which no alternative exists, are so dangerous and of such little use that under risk-utility analysis, manufacturer would bear cost of liability of harm to others.
  • “Here, the trial court should have permitted the jury to consider whether, because of the dimensions of the pool and slipperiness of the bottom, the risks of injury so outweighed the utility of the product as to constitute a defect.”
  • It was unnecessary for the plaintiff to prove the existence of alternative, safer, designs. As a luxury item, even if there are were alternative methods of making bottoms for above-ground pools, the jury might have found that the risk posed by the pool outweighed its utility.

This case basically attempted to create absolute liability on an entire category of inherently dangerous products, even though there were no alternative designs available.

Note: This case has been overruled by statute. A product cannot be found defective in design if “there was not a practical and technically feasible alternative design that would have prevented the harm without substantially impairing the reasonably anticipated or intended function of the product.” N.J. Stat. Ann. § 2A:58C-3 (West).

Restatement (Third) of Torts: Prod. Liab. § 2 cmt. D. Categories of Product Defect. Common and widely distributed products such as alcoholic beverages, firearms, and above-ground swimming pools may be found to be defective only upon proof of the requisite conditions in Subsection (a), (b), or (c). If such products are defectively manufactured or sold without reasonable warnings as to their danger when such warnings are appropriate, or if reasonable alternative designs could have been adopted, then liability under §§ 1 and 2 may attach. Absent proof of defect under those Sections, however, courts have not imposed liability for categories of products that are generally available and widely used and consumed, even if they pose substantial risks of harm.