MESOTHELIOMA | 2026-10-26

Strict Liability for Failure to Warn in California Asbestos Cases: What Anderson v. Owens-Corning and the “State of the Art” Defense Really Mean

A core theory in every mesothelioma case is that the manufacturer failed to warn of the dangers of asbestos. California recognizes strict liability for failure to warn — but Anderson v. Owens-Corning allows a defendant to introduce “state of the art” evidence, tying liability to risks that were known or scientifically knowable when the product was made.

In nearly every California mesothelioma and asbestos-disease case, one of the central theories is that the manufacturer failed to warn of the dangers of its asbestos-containing products. California recognizes strict products liability for a failure to warn, which does not require the victim to prove

Mesothelioma is caused almost exclusively by exposure to asbestos, and the companies that made and sold asbestos-containing products are the principal defendants in California asbestos litigation. A failure-to-warn claim asserts that those manufacturers put dangerous products into commerce without adequate warnings of the hazards. California law makes such claims available under strict products liability, but the California Supreme Court has defined the theory in a way that incorporates a key limitation: the "state of the art." Understanding how strict-liability failure-to-warn operates, and how Anderson v. Owens-Corning shaped it, is central to any asbestos case. This article explains the doctrine, the defense, and what each means in practice.

Two Theories of Strict Products Liability

California strict products liability generally proceeds on two distinct theories: design defect and failure to warn. A design-defect claim contends that the product itself was unreasonably dangerous as designed. A failure-to-warn claim contends that the product, whatever its design, was defective because it lacked adequate warnings or instructions about its dangers. In asbestos cases, the failure-to-warn theory is frequently central: asbestos products such as insulation, gaskets, and friction materials released hazardous fibers in use, and the claim is that manufacturers failed to warn workers and consumers of that danger. The two theories have different elements and different defenses, and the state-of-the-art issue arises specifically in the failure-to-warn context.

What Anderson v. Owens-Corning Decided

In Anderson v. Owens-Corning Fiberglas Corp. (1991) 53 Cal.3d 987, the California Supreme Court confronted whether a manufacturer could introduce state-of-the-art evidence — evidence of what was scientifically knowable about a product's dangers at the relevant time — in a strict-liability failure-to-warn case. The Court held that such evidence is admissible. It reasoned that a manufacturer's duty to warn in strict liability is tied to risks that were known or knowable in light of the generally recognized and prevailing best scientific and medical knowledge available at the time of manufacture and distribution. In other words, a manufacturer cannot be held strictly liable for failing to warn of a danger that was scientifically unknowable when the product was made. Anderson is a foundational California decision and governs the shape of every asbestos failure-to-warn claim.

Strict Liability Is Not Absolute Liability

Anderson makes an important conceptual point: strict liability for failure to warn is not the same as absolute liability. Although a failure-to-warn plaintiff need not prove the manufacturer was negligent in the traditional sense, the manufacturer's duty is bounded by what was knowable. The Court declined to impose liability for failing to warn of risks that no one in the relevant scientific community could have known about at the time. This "knowability" limitation distinguishes strict-liability failure-to-warn from true absolute liability, under which a manufacturer would be liable regardless of what was knowable. For asbestos cases, the distinction frames the central factual battleground: what was known or knowable about the dangers of asbestos, and when.

The State-of-the-Art Battleground in Asbestos Cases

Because Anderson ties liability to knowable risk, asbestos litigation often turns into a contest over the historical state of scientific and medical knowledge. Plaintiffs typically marshal extensive evidence that the dangers of asbestos were known or knowable decades before many defendants began warning — pointing to early medical literature, industry studies, and internal documents showing awareness of asbestos disease. Defendants invoke the state of the art to argue that the specific risk at issue was not yet established at the time their product was made. In the asbestos context, the plaintiff's evidence is frequently powerful: the hazards of asbestos were documented in scientific and medical literature well before the exposures at issue in many cases, which undercuts a state-of-the-art defense premised on the danger being unknowable. The strength of each side's historical proof is often decisive.

Knowable, Not Just Known

A subtle but important feature of the Anderson standard is that the duty extends to risks that were knowable, not merely those that were actually known to the particular manufacturer. The test looks to the generally recognized and prevailing best scientific and medical knowledge available at the time — an objective measure of what the scientific community could have known — rather than to the subjective knowledge of the individual defendant. A manufacturer cannot escape liability simply by showing that it personally did not know of the danger if the danger was scientifically knowable through reasonably available information. This objective "knowability" standard prevents a manufacturer from benefiting from its own failure to keep abreast of the science, while still protecting it from liability for truly unknowable risks.

The Rx-Drug Comparison: Carlin v. Superior Court

The Anderson "knowable risk" standard was reaffirmed and extended in Carlin v. Superior Court (1996) 13 Cal.4th 1104, where the California Supreme Court held that a prescription-drug manufacturer may be held strictly liable for failure to warn of risks that were known or reasonably scientifically knowable at the time of distribution. Carlin confirmed that the special protection prescription drugs receive against strict-liability design-defect claims does not eliminate strict-liability failure-to-warn claims, and it applied the same knowable-risk formulation that governs other products. Together, Anderson and Carlin establish that across product categories, California strict-liability failure-to-warn is anchored to the knowable-risk standard — a consistent principle that asbestos litigants can rely on.

Causation Still Must Be Proved

Establishing a failure-to-warn defect is only part of an asbestos case; the victim must also prove causation. Under Rutherford v. Owens-Illinois, Inc. (1997) 16 Cal.4th 953, a plaintiff in an asbestos case must show that exposure to the defendant's product was a substantial factor in contributing to the aggregate dose of asbestos the plaintiff inhaled, and hence to the risk of developing mesothelioma. This causation standard works alongside the failure-to-warn theory: the plaintiff proves both that the product was defective for lack of adequate warning and that exposure to it was a substantial factor in causing the disease. The two inquiries are distinct, and a strong asbestos case develops the evidence for each — product identification and exposure for causation, and the historical science for the knowable-risk failure-to-warn element.

Component Parts and the Scope of the Duty

California law also defines whose products can give rise to failure-to-warn liability. In O'Neil v. Crane Co. (2012) 53 Cal.4th 335, the California Supreme Court held that a manufacturer generally is not liable in strict liability or negligence for harm caused by asbestos-containing products made by others that were later used with or attached to the manufacturer's own product, unless the manufacturer's own product contributed substantially to the harm or the manufacturer participated substantially in creating the harmful combined use. O'Neil shapes which manufacturers a plaintiff can reach: the focus is on the defendant's own asbestos-containing product and the warnings it gave, not on asbestos introduced by others. Identifying the correct defendants under O'Neil is an important part of building a viable failure-to-warn case.

Practical Guidance for Asbestos Victims and Families

For a California family facing a mesothelioma diagnosis, several practical points follow. First, the failure-to-warn theory is central and does not require proving traditional negligence — but it does require confronting the state-of-the-art defense with strong historical and scientific evidence that the dangers were known or knowable. Second, the case requires rigorous product identification and exposure proof to satisfy the Rutherford substantial-factor causation standard. Third, the choice of defendants must account for O'Neil, focusing on the makers of the asbestos-containing products to which the victim was actually exposed. Fourth, because asbestos diseases have long latency periods and many potential defendants and bankruptcy trusts may be involved, early and thorough investigation is critical. Experienced asbestos counsel assembles the historical record, the exposure evidence, and the full roster of responsible parties.

Negligence and Strict Liability Compared

A failure-to-warn case is frequently pleaded on two parallel theories: strict liability and negligence. The theories overlap but are not identical. Strict-liability failure to warn, as shaped by Anderson, focuses on whether the product was defective for lack of an adequate warning of a known or knowable risk, without requiring proof that the manufacturer breached a standard of care. Negligent failure to warn asks whether the manufacturer acted unreasonably — whether a reasonably prudent manufacturer, knowing what this manufacturer knew or should have known, would have warned. In the asbestos setting the two theories often converge on the same historical evidence about what was known and when, but the negligence theory can allow a plaintiff to emphasize a manufacturer's conduct — its failure to test, to heed warning signs, or to act on internal knowledge. Pleading both preserves the plaintiff's options and lets the evidence of the manufacturer's actual knowledge and conduct do work under the negligence theory even as the strict-liability theory anchors liability to the objective knowable-risk standard.

Punitive Damages and Manufacturer Conduct

Where the evidence shows that a manufacturer knew of the dangers of asbestos and concealed them or failed to warn in conscious disregard of the risk, punitive damages may be available. Under Civil Code §3294, a plaintiff may recover punitive damages on proof, by clear and convincing evidence, that the defendant is guilty of oppression, fraud, or malice — which can include a conscious disregard of the safety of others. In asbestos cases, punitive-damages claims are frequently built on internal corporate documents demonstrating that a manufacturer understood the hazards long before it warned, and on evidence that the failure to warn was a deliberate business decision rather than an innocent oversight. For a corporate defendant, §3294 further requires that the oppression, fraud, or malice be on the part of an officer, director, or managing agent, or ratified by one. The availability of punitive damages can significantly affect both the value and the trajectory of an asbestos case, and it is one reason the historical record of what the manufacturer knew is developed so thoroughly.

Bankruptcy Trusts and the Full Recovery Picture

A failure-to-warn claim against solvent manufacturers is usually only part of a mesothelioma victim's recovery picture. Many of the companies that made asbestos-containing products reorganized in bankruptcy and funded asbestos personal-injury trusts to pay current and future claims. These trusts pay according to their own trust distribution procedures, based on documented exposure to the bankrupt entity's products, and they operate outside the tort system. A thorough case therefore pursues recovery across multiple channels in parallel: tort claims against solvent manufacturers (where the Anderson failure-to-warn theory and Rutherford causation govern), trust claims against bankrupt manufacturers, and any available claims against other responsible parties. Coordinating these channels requires careful attention to exposure evidence, because the same work history must support each claim, and to the rules governing setoffs and the interaction between trust recoveries and tort judgments. Because mesothelioma has a long latency period and a victim may have encountered dozens of products over a working lifetime, assembling the complete roster of solvent defendants and applicable trusts early — and documenting exposure to each — is often what determines whether a victim obtains a full recovery or leaves significant compensation unclaimed. Experienced asbestos counsel maps this entire landscape at the outset of the case. Doing so ensures that the failure-to-warn claims against solvent manufacturers, the trust claims against bankrupt ones, and the exposure evidence that supports them all are developed together, rather than discovered piecemeal after key opportunities have passed. That coordinated approach, begun early, is consistently what allows a mesothelioma victim and family to pursue the fullest compensation the law makes available to them.

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Frequently Asked Questions

What is a failure-to-warn claim in an asbestos case?

It is a strict products liability theory asserting that a manufacturer put an asbestos-containing product into commerce without adequate warnings of its dangers. Unlike negligence, strict-liability failure to warn does not require proving the manufacturer was careless, but under Anderson the duty is tied to risks that were known or knowable at the time.

What did Anderson v. Owens-Corning decide?

In Anderson v. Owens-Corning Fiberglas Corp. (1991) 53 Cal.3d 987, the California Supreme Court held that a manufacturer may introduce state-of-the-art evidence in a strict-liability failure-to-warn case, and that liability attaches to risks known or knowable in light of the best scientific and medical knowledge available at the time of manufacture and distribution.

What is the "state of the art" defense?

It is the manufacturer's argument that the specific danger was not scientifically knowable when the product was made and sold, so there was no duty to warn of it. Anderson makes such evidence admissible, but in asbestos cases the hazards were often documented in the scientific literature long before the exposures, undercutting the defense. Call Trembach Law Firm at (213) 645-2246.

Does strict liability mean the manufacturer is automatically liable?

No. Anderson makes clear that strict liability for failure to warn is not absolute liability. The duty is bounded by what was knowable; a manufacturer is not liable for failing to warn of a risk that was scientifically unknowable at the time. The central question becomes what was known or knowable about asbestos, and when.

Is the standard based on what the manufacturer actually knew?

No. The test is objective — it looks to the generally recognized and prevailing best scientific and medical knowledge available at the time, not the individual manufacturer's subjective knowledge. A manufacturer cannot escape liability by showing it personally did not know of a danger that was scientifically knowable.

How does Carlin v. Superior Court relate to Anderson?

In Carlin v. Superior Court (1996) 13 Cal.4th 1104, the Court applied the Anderson knowable-risk standard to prescription drugs, holding manufacturers strictly liable for failure to warn of known or reasonably scientifically knowable risks. Together the cases confirm that California anchors strict-liability failure-to-warn to the knowable-risk standard across product categories.

Do I still have to prove causation?

Yes. Under Rutherford v. Owens-Illinois, Inc. (1997) 16 Cal.4th 953, you must show exposure to the defendant's asbestos product was a substantial factor contributing to the aggregate dose and the risk of mesothelioma. Failure-to-warn defect and causation are distinct elements, both of which must be proved. Call Trembach Law Firm at (213) 645-2246.

Which manufacturers can be held liable?

Under O'Neil v. Crane Co. (2012) 53 Cal.4th 335, a manufacturer is generally not liable for asbestos in products made by others merely used with its product, unless its own product contributed substantially to the harm or it participated substantially in the harmful combined use. The focus is on the makers of the asbestos products to which the victim was actually exposed.

Talk to a California Mesothelioma Lawyer About a Failure-to-Warn Claim

If you or a loved one developed mesothelioma from asbestos exposure, a strict-liability failure-to-warn claim is often central — and meeting the Anderson knowable-risk standard requires strong historical and scientific proof. Trembach Law Firm, led by Anatolii Trembach (LL.M.; admitted in California), builds the historical record, the exposure evidence, and the full roster of responsible manufacturers. Call (213) 645-2246 for a free, confidential consultation.

Contact Trembach Law Firm at (818) 514-7680 for a confidential consultation.

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