Illegality Trumps Comparative Fault: Tenth Circuit Predicts Kansas Bars Product Liability Claims Arising from a Plaintiff’s Criminal Misuse

Introduction

This published decision of the United States Court of Appeals for the Tenth Circuit, Messerli v. AW Distributing, addresses whether a plaintiff can maintain Kansas products liability claims when the injury flows directly from the plaintiff’s own criminal conduct. The case arises from the tragic death of Kyle Messerli, who became addicted to inhaling difluoroethane (DFE) from computer duster cans and died of acute DFE intoxication. His father, Robbin Messerli, sued several manufacturers and distributors—AW Distributing, Inc.; AW Product Sales & Marketing, Inc.; Falcon Safety Products, Inc.; and Norazza, Inc.—asserting wrongful death and survival claims under the Kansas Product Liability Act (KPLA). The complaint alleged that defendants knew of widespread inhalant abuse and failed to adopt reasonably safe designs, warnings, and marketing practices (including allegedly ineffective bitterants).

Defendants moved to dismiss, invoking Kansas’s common-law “illegality defense” (sometimes discussed alongside in pari delicto and the wrongful-conduct doctrine), arguing that because huffing DFE is illegal under Kansas law, the claims are barred where the plaintiff’s own illegal acts proximately caused the harm. The district court agreed and dismissed. On appeal, the Tenth Circuit affirmed, holding that under Kansas law the illegality defense remains viable, was not abrogated by the comparative negligence regime or the KPLA, and bars recovery where the injury is caused by the plaintiff’s illegal conduct. The panel also denied the renewed motion to certify the question to the Kansas Supreme Court.

Summary of the Judgment

The Tenth Circuit affirmed dismissal of the complaint under Rule 12(b)(6). Applying Kansas substantive law in this diversity case, the court held:

Kansas recognizes an illegality defense that precludes recovery when the plaintiff’s own illegal act proximately causes the injury.
Neither the Kansas Product Liability Act nor Kansas’s comparative negligence statute abrogates the illegality defense.
Illegality is not an “analogous defense” swept aside by the adoption or judicial expansion of comparative fault; its policy basis is independent from comparative negligence.
On the face of the complaint, Kyle’s violation of K.S.A. § 21-5712 (unlawful abuse of toxic vapors) and his death from acute DFE intoxication established the elements of the affirmative defense, warranting dismissal.
The panel made an Erie prediction that the Kansas Supreme Court would apply the illegality defense to products liability claims under these facts and denied the request to certify the question to that court.

Analysis

The Statutory and Doctrinal Framework

Kansas products liability is governed by the KPLA, K.S.A. §§ 60-3301 et seq., which consolidates products liability theories into a unitary cause of action. Where the KPLA is silent, Kansas common law supplies the rules. Under Kansas common law:

Manufacturers owe duties not only for intended uses but also for reasonably foreseeable misuses, including foreseeable “abuse,” and must warn against such foreseeable misuses (Kennedy v. City of Sawyer; Wheeler v. John Deere; Richter v. Limax).
Affirmative defenses—including “illegality”—are preserved by K.S.A. § 60-208(c)(1)(H) and by common law absent clear legislative abrogation.
The illegality defense bars claims when the plaintiff’s illegal act proximately caused the injury.

Kansas’s comparative negligence statute, K.S.A. § 60-258a, adopts modified comparative fault (recovery permitted only if plaintiff’s negligence is less than 50%) and has been judicially extended to products cases to displace several “all-or-nothing” defenses that are analogous to contributory negligence (assumption of risk, product misuse, unreasonable use). The question was whether “illegality” is among those displaced defenses. The Tenth Circuit held it is not.

Precedents Cited and Their Influence

Kansas City v. Orr, 61 P. 397 (Kan. 1900), and Richards v. Fleming Coal Co., 179 P. 380 (Kan. 1919): Early Kansas recognition that a plaintiff cannot recover on a cause of action requiring proof of his own illegal act.
Beggerly v. Walker, 397 P.2d 395 (Kan. 1964): Clarified the causation requirement—illegality bars recovery only when the illegal act has a causal connection to injury.
Zimmerman v. Brown, 306 P.3d 306 (Kan. App. 2013): Modern Kansas expression that illegality is a valid defense in tort if the plaintiff’s illegal act proximately caused the injury; shows the defense survived adoption of comparative fault.
Kennedy v. City of Sawyer, 618 P.2d 788 (Kan. 1980): Extended comparative negligence principles to product cases and abrogated several all-or-nothing, contributory-negligence-like defenses (assumption of risk, misuse, unreasonable use). Messerli relied on Kennedy to argue illegality should be treated similarly; the Tenth Circuit disagreed, reasoning illegality is conceptually distinct.
Arredondo v. Duckwall Stores, Inc., 610 P.2d 1107 (Kan. 1980), and Forsythe v. Coats Co., 639 P.2d 43 (Kan. 1982): Emphasized Kansas policy of apportioning fault and applying comparative negligence broadly—but did not address illegality specifically.
Simmons v. Porter, 312 P.3d 345 (Kan. 2013): Abrogated implied assumption of risk; cited as part of Kansas’s general preference for comparative fault, but again not about illegality.
Pizel v. Zuspann, 795 P.2d 42 (Kan. 1990): Legal malpractice is negligence subject to comparative negligence; Zimmerman nonetheless recognized illegality in that context, undermining the claim that comparative fault impliedly abolished illegality.
Ed DeWitte Ins. Agency, Inc. v. Financial Associates Midwest, Inc., 427 P.3d 25 (Kan. 2018): Presumption against abrogating common law absent clear legislative intent—applied to conclude the KPLA did not abolish illegality.
Inge v. McClelland, 725 F. App’x 634 (10th Cir. 2018): Applying New Mexico law, held the wrongful-conduct doctrine is compatible with comparative fault; used here persuasively to support compatibility of illegality with comparative fault.
Barker v. Kallash, 468 N.E.2d 39 (N.Y. 1984): Clarified that public policy against aiding a lawbreaker is independent of contributory/comparative negligence; relied on to explain why illegality is not an “analogous” defense to comparative negligence.
Jacobson v. Pfizer, Inc., 618 F. App’x 509 (11th Cir. 2015); Price v. Purdue Pharma Co., 920 So. 2d 479 (Miss. 2006); Pappas v. Clark, 494 N.W.2d 245 (Iowa Ct. App. 1992); Orzel by Orzel v. Scott Drug Co., 537 N.W.2d 208 (Mich. 1995); Greenwald v. Van Handel, 88 A.3d 467 (Conn. 2014); Ryan v. Hughes-Ortiz, 959 N.E.2d 1000 (Mass. App. Ct. 2012): Comparative authority recognizing wrongful-conduct/illegality bars in tort and products claims despite comparative fault regimes.
Dugger v. Arredondo, 408 S.W.3d 825 (Tex. 2013): Contrary Texas authority; distinguished because Texas’s proportionate responsibility statute expressly requires comparison even for conduct “that violates an applicable legal standard”—Kansas has no such statutory language.
Restatement (Second) of Torts § 889 (1979): Endorses an illegality bar when a violated statute is designed to prevent the very type of harm that occurred; cited to align Kansas with mainstream tort doctrine.

Legal Reasoning

Illegality exists at Kansas common law and was preserved. Kansas decisions since 1900 recognize the rule that courts will not aid a plaintiff whose claim requires proof of his own illegality, provided there is a causal nexus between the unlawful act and the injury (Orr; Beggerly; Zimmerman). The KPLA does not abrogate that rule, and Kansas courts presume no abrogation absent clear legislative intent (Ed DeWitte).
Comparative negligence did not abrogate illegality. While Kennedy and progeny swept away certain all-or-nothing defenses that mirror contributory negligence (assumption of risk, misuse, unreasonable use), illegality rests on a different, independent policy: courts should not lend assistance to those seeking relief for injuries proximately caused by their own crimes. Comparative fault allocates blame among negligent actors; illegality denies a cause of action where the plaintiff’s criminality is the direct cause of the injury.
Comparative and Restatement support. Other jurisdictions (and the Restatement) apply wrongful-conduct/illegality bars alongside comparative fault; thus, no structural incompatibility exists between the doctrines. Texas’s contrary result in Dugger turns on unique statutory text not present in Kansas.
Erie prediction. The Tenth Circuit predicted the Kansas Supreme Court would adhere to illegality in products cases because the policy is distinct from comparative negligence and because Kansas appellate cases post-comparative-fault continue to apply illegality in tort contexts (Zimmerman). The court rejected the request to certify after an adverse ruling, a discretionary call consistent with federal practice.
Application to the pleadings. On a motion to dismiss, courts may dismiss when the complaint itself establishes the elements of an affirmative defense. Here, the complaint alleged: (a) Kyle repeatedly “huffed” computer duster; (b) such conduct violates K.S.A. § 21-5712 (unlawful abuse of toxic vapors); and (c) he died from acute DFE intoxication—the very harm the statute addresses. Those admissions satisfy the elements of illegality and proximate cause, barring recovery as a matter of law.

Why Illegality Is Not an “Analogous Defense” to Contributory Negligence

Kennedy’s “analogous defense” category targeted defenses that function like contributory negligence—they focus on the plaintiff’s carelessness and often require the factfinder to weigh relative fault. Illegality is different: it is a threshold bar rooted in a public policy that courts will not facilitate recovery for injuries proximately caused by the plaintiff’s criminality. As the New York Court of Appeals put it in Barker v. Kallash, this policy “has always existed independently” of contributory/comparative negligence. That is why Kansas decisions abrogating assumption of risk or misuse do not implicitly abrogate illegality.

The Role of Kansas’s Toxic Vapors Statute

K.S.A. § 21-5712 criminalizes the possession, purchase, use, smelling, or inhalation of “toxic vapors” with the intent to produce euphoria or dulled senses. Halogenated hydrocarbons—such as DFE—are covered. By pleading that Kyle knowingly huffed DFE and died from acute DFE intoxication, the complaint itself tied the death to the specific risk the statute seeks to prevent. That alignment made the illegality defense especially straightforward under the Restatement’s harm-matches-risk principle (§ 889 cmt. b).

Impact

On Kansas Products Liability and Tort Practice

Substantive rule cemented: The illegality defense remains good law in Kansas and applies to products liability claims where the plaintiff’s criminal act proximately caused the injury.
Comparative fault boundary: The decision delineates the boundary of Kansas’s comparative negligence regime and clarifies that not every “plaintiff conduct” defense is subsumed into comparative apportionment.
Pleading-stage dismissals: Defendants can obtain dismissal at Rule 12(b)(6) if the complaint itself establishes the elements of illegality and proximate cause. Plaintiffs should plead cautiously; nevertheless, if illegality and causal nexus are inherent to the factual narrative, amendment may not cure the bar.
Foreseeable misuse does not guarantee recovery: Even though manufacturers must warn about reasonably foreseeable misuses, a claim is barred if the injury flows from the plaintiff’s criminal misuse. This rebalances incentives: manufacturers still face duties to design and warn, but courts will not award damages to a plaintiff injured by his own crime.
Scope beyond inhalants: Expect invocation of this defense in cases involving illegal drug misuse (e.g., prescription diversion), illegal street racing, unlawful weapons possession/use, and other criminal acts that directly produce the injury.
Third-party and derivative claims: The opinion addresses only the wrongdoer’s claim. Claims by innocent third parties (bystanders, guardians, estates where decedent’s conduct was not illegal or not causally connected) may stand on different footing.
Certification posture: The Tenth Circuit’s refusal to certify after an adverse ruling signals federal comfort making Erie predictions where Kansas appellate law provides sufficient guidance.

For Manufacturers and Insurers

Defense toolkit: Plead illegality affirmatively (K.S.A. § 60-208(c)(1)(H)) and move to dismiss when the complaint admits illegality and causation.
Evidence strategy: If not apparent on the pleadings, develop undisputed proof that the plaintiff’s conduct violated a criminal statute designed to prevent the harm suffered.
Risk assessment: The decision reduces exposure in suits where criminal misuse is the proximate cause, even where misuse is foreseeable and warnings are contested.

For Plaintiffs

Identify non-illegal causation theories: Viable theories may require showing that the injury resulted from a defect that would have caused harm independently of the plaintiff’s illegal act, or that the illegal act was too remote to be the proximate cause.
Consider alternative plaintiffs: Claims by nonwrongdoers (e.g., family members for their own independent harms, bystanders) may avoid the bar.
Beware admissions: Allegations that squarely concede criminal conduct causing the injury likely foreclose litigation at the outset.

Complex Concepts Simplified

Illegality defense: A common-law rule that bars a plaintiff from recovering if the plaintiff’s own criminal act proximately caused the injury for which damages are sought.
In pari delicto: A related doctrine that prevents courts from resolving disputes between two wrongdoers. It involves weighing relative culpability and is distinct from illegality’s binary bar.
Wrongful-conduct doctrine: A general label in some jurisdictions for defenses that preclude recovery based on the plaintiff’s illegal or immoral acts. In Kansas, “illegality” is the operative affirmative defense.
Comparative negligence (K.S.A. § 60-258a): A statutory system that reduces damages in proportion to the plaintiff’s negligence and bars recovery at 50% fault or higher.
“Analogous defenses” abrogated by comparative fault: Defenses such as assumption of risk, misuse, and unreasonable use that mirror contributory negligence and were displaced in products cases by Kennedy v. City of Sawyer.
Proximate cause: A causal connection sufficiently direct that the law recognizes the defendant’s (or here, the plaintiff’s) act as producing the injury in a natural, continuous sequence.
KPLA (K.S.A. §§ 60-3301 et seq.): Kansas’s framework for products liability, merging theories into a unified cause of action and leaving gaps to be filled by common law.
Erie prediction: In diversity cases, when a state’s highest court has not addressed an issue, federal courts predict how that court would rule based on available state law sources.
Rule 12(b)(6) dismissal on an affirmative defense: Although affirmative defenses typically require proof, a court may dismiss at the pleading stage when the complaint itself establishes all elements of the defense.

Practical Pathways and Limits After Messerli

When the defense applies: The plaintiff’s conduct violates a criminal statute; the harm is the very risk the statute aims to prevent; and the complaint or undisputed facts show a proximate causal link.
When it may not apply: The plaintiff’s conduct is not criminal; the illegal act is merely collateral or too remote; the harm is not the type the statute targets; or the claimant is an innocent third party whose cause of action does not rely on the wrongdoer’s illegal act.
Possible future debates: Whether Kansas recognizes exceptions (e.g., protected classes, substantial disparity of culpability, minors, or coerced conduct). Messerli does not decide these questions.
Legislative possibility: If Kansas wished to fold illegality into comparative fault (as Texas did), it would need explicit statutory language. As of Messerli, no such text exists.

Conclusion

Messerli v. AW Distributing firmly predicts that Kansas’s illegality defense remains a complete bar to recovery in products liability actions when the plaintiff’s criminal act proximately causes the injury. The decision draws a principled line between comparative negligence—an apportionment regime concerned with degrees of fault—and illegality, a threshold bar rooted in public policy against aiding a lawbreaker. By confirming the defense’s continued vitality and compatibility with the KPLA, the Tenth Circuit provides clear guidance: foreseeable misuse and manufacturer duties do not override an illegality bar when the harm results from the plaintiff’s own criminal misuse. Practically, this decision equips defendants to seek early dismissal and cautions plaintiffs to evaluate whether their theories can escape the causal force of criminal conduct. Its impact will likely extend beyond inhalant cases to any tort claims in Kansas where the plaintiff’s injury is directly tied to a statutory crime designed to prevent the very harm suffered.