Products Liability Law Daily Wrap Up, EXPERT EVIDENCE—HOUSEHOLD PRODUCTS—E.D. Wis.: Wisconsin federal court splits the difference in Adirondack chair liability suit, (Mar 12, 2026)

By Wendy Biddle, J.D.

Dueling expert testimony on oxidative degradation creates genuine factual disputes for the jury.

A federal court in Milwaukee, Wisconsin has granted in part and denied in part a motion for summary judgment filed by Adams Manufacturing Company in a product liability suit brought by a plaintiff who claims he was rendered a quadriplegic when an injection-molded plastic Adirondack chair collapsed beneath him. The court dismissed the plaintiff's manufacturing defect and warning defect claims with prejudice, while permitting the design defect and negligence claims to proceed to trial (Scanlan v. Adams Manufacturing Co., No. 2:22-cv-00586-PP (E.D. Wis. Mar. 6, 2026)).

Background. Adams Manufacturing makes a line of injection-molded consumer products, including a residential plastic Adirondack chair marketed as the Real Comfort Adirondack (RCA). The subject chair, manufactured in April 2021 and composed of 85% polypropylene and 15% co-polymer, was purchased by Homestead Suites, Inc. in June 2021 and placed around a fire pit at a guest house property.

On the evening of Oct. 29, 2021, the plaintiff and several friends were renting the guest house for a weekend vacation. The plaintiff, who had consumed at least twelve beers over the course of the day, sat on the left armrest of the chair while another guest was already seated in the chair's main seat. The two together weighed approximately 320 pounds—70 pounds over the chair's 250-pound weight limit, as marked in warnings molded into the underside of the chair and on a stick-on label. After sitting on the armrest for approximately 10 to 15 minutes, the chair broke. The plaintiff testified that he blacked out and has no memory of the chair breaking or the fall. He was found unable to move his hands or legs; blood drawn at approximately 1:00 a.m. showed a blood alcohol concentration of 0.238.

The plaintiff alleged the incident rendered him a quadriplegic and filed suit asserting strict product liability claims on theories of manufacturing defect, design defect, and warning defect, as well as common law negligence.

Expert testimony dispute. The central factual controversy in the case concerns whether the chair's polypropylene material had undergone oxidative degradation that compromised its structural integrity. The parties jointly collected test data, including thin surface shavings from five locations on the chair, which were analyzed using Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR).

The DSC testing showed no material defects or processing irregularities. The FTIR results, however, revealed that oxidation was present on the outermost surface of the chair material, though not in its core or bulk.

The plaintiff's materials expert, Dr. Russell Dunn, concluded that the oxidation was "severe" and had caused embrittlement of the chair, meaning it would snap rather than bend under force, a condition he called "brittle fracture." Dr. Dunn opined that a properly functioning, non-degraded chair would flex visibly under load, providing a user with a warning that the arm could not bear weight. Because this chair had degraded, he argued that this warning mechanism was absent. Dr. Dunn proposed several alternative designs that could have mitigated the degradation, including the addition of antioxidant additives to the polypropylene, the substitution of nylon for polypropylene, thicker chair walls, or the addition of calcium carbonate filler.

The defendant's expert, Dr. Marc Zupan, reached the opposite conclusion, finding that the oxidation was "surface-specific" and had not altered the internal structure of the chair from its original state. Dr. Zupan concluded there was no material manufacturing defect or material property anomaly in the subject chair, and that the chair's failure was caused by the excess weight placed on it rather than any degradation.

Manufacturing defect claim. The court granted summary judgment on this claim without extended analysis. Under Wisconsin law, a manufacturing defect requires that the product departed from its intended design. Because Dr. Zupan found no departure from the intended design and the plaintiff did not respond to the defendant's argument on this point, effectively conceding it, the court found the undisputed record required judgment for the manufacturer.

Design defect claim. The court denied summary judgment, finding that the competing expert opinions on oxidative degradation created a genuine dispute of material fact.

The defendant advanced two primary arguments. First, it contended that polypropylene is an "inherent characteristic" of the chair and that Wisconsin's product liability statute bars claims where damage is caused by an inherent characteristic of the product. The court rejected this argument on two grounds. Under the current version of Wis. Stat. §895.047(3)(d), the inherent characteristic bar applies only when the characteristic "would be recognized by an ordinary person with ordinary knowledge common to the community." The court found that oxidative degradation of polypropylene does not meet that standard; an average consumer purchasing an outdoor chair would reasonably assume it was designed to withstand outdoor conditions. Further, the court found that polypropylene is not an inherent characteristic of an Adirondack chair at all, since such chairs can be made from multiple different materials, and adding antioxidants to the polymer would not transform the product into something unrecognizable.

Second, the manufacturer argued that the plaintiff failed to identify a reasonable alternative design that would have actually prevented the harm. The court was unpersuaded. Although the defendant attacked specific proposals as based on different product lines, it failed to meaningfully rebut the plaintiff's core proposal: adding antioxidant additives to the polypropylene. The court had previously rejected the defendant's argument that Dr. Dunn had not adequately presented antioxidant additives as an alternative design. With that ruling in place, and with conflicting expert testimony from Dr. Dunn and Dr. Zupan on whether the chair was defectively designed, the court concluded that resolution of the design defect claim required a jury to weigh competing expert opinions. Citing the Seventh Circuit's guidance that summary judgment is inappropriate where the trier of fact must choose between dueling experts, the court denied the motion.

Warning defect claim. The court granted summary judgment on this claim, finding that the plaintiff could not establish that any warning would have changed his behavior. The analysis turned on the testimony of the plaintiff's own human factors expert, Joellen Gill. While Gill criticized the warnings as inadequate in placement and durability, noting that a removable sticker label loses effectiveness once removed and that a warning printed on the underside of a chair is unlikely to be noticed, her opinions also acknowledged critical limitations. Gill explained that consumers who are familiar with a product are unlikely to seek out warnings; that if a warning conflicts with a user's prior experience, the user may disregard it; and that the plaintiff, having sat on chair arms before, would have had an "expectancy" that the chair would hold him. The plaintiff himself confirmed at deposition that he did not look for a warning and likely would not have noticed one given the dark conditions. The plaintiff also failed to provide examples of alternative warnings that could have prevented the harm. The court concluded that, on these facts, no reasonable jury could find that a better-placed or more prominent warning would have made a difference, and granted summary judgment for the defendant.

Intoxication defense. Wisconsin's product liability statute creates a rebuttable presumption that a plaintiff's intoxication caused his injury when the plaintiff's blood alcohol content is 0.08% or higher at the time of the incident. Wis. Stat. §895.047(3)(a). With Scanlan's BAC established at 0.238, the manufacturer argued this provision entitled it to judgment. The court declined to resolve the defense at summary judgment, clarifying that the intoxication provision is not a complete defense but rather an evidentiary presumption the plaintiff can rebut by showing "that it is more probable than not that there was an additional cause which produced the plaintiff's injury." Because disputed facts remain as to the design defect claim, causation cannot be determined as a matter of law. The plaintiff will have the opportunity at trial to present evidence that the chair's alleged design defect was an additional contributing cause of his injuries.

Negligence claim. The court also denied summary judgment on the common law negligence claim, concluding that the same disputed material facts about the existence of a design defect that defeated summary judgment on the statutory claim equally precluded judgment on whether Adams breached its duty of care.

The case is No. 2:22-cv-00586-PP.

Judge: Pepper, P.

Attorneys: David S. Blinka (Habush Habush & Rottier SC) for Ronald Scanlan. Alexandrea Marie Smith (Ogden Murphy Wallace PLLC) for Adams Manufacturing Co.

Companies: Adams Manufacturing Co.

MainStory: TopStory DesignManufacturingNews ExpertEvidenceNews HouseholdProductsNews WisconsinNews