When a product is sold without a hazardous component and a third party later adds it, does the original manufacturer owe a duty to warn about the danger? That question defined the so-called bare-metal defense, and the Supreme Court addressed it in Air & Liquid Systems Corp. v. DeVries, 586 U.S. 446 (2019). The case arose in an asbestos setting under maritime law, but the framework it adopted is cited well beyond that context, including in cases involving replacement parts, accessories, and integrated systems.
The Facts and the Question
Two Navy veterans developed cancer after exposure to asbestos while serving aboard ships. Their claims were against manufacturers of equipment such as pumps, blowers, and turbines. Those manufacturers delivered their products to the Navy without asbestos insulation or replacement parts, but the products were designed in a way that required asbestos insulation to function and be safe at operating temperatures. The Navy added asbestos-containing materials, manufactured by others, after delivery. The manufacturers argued they could not be responsible for hazards in products they did not make or sell.
The Holding
The Court held that, in the maritime tort context, a product manufacturer has a duty to warn when its product requires incorporation of a part, the manufacturer knows or has reason to know that the integrated product is likely to be dangerous for its intended uses, and the manufacturer has no reason to believe that the product's users will realize that danger. The Court framed the question in terms of foreseeability and the manufacturer's connection to the integrated product, rejecting both a rule of blanket immunity and a rule that would impose liability whenever it was merely foreseeable that a third-party part might be added. The distinction is between a product that requires a hazardous part to function as intended and one for which the later addition is an optional or unforeseeable choice.
Why the Opinion Matters Outside Asbestos
The decision is narrower than defense briefs sometimes suggest, and broader than plaintiffs sometimes assume. It is a maritime case, so state courts applying their own tort law are not bound by it. But many state courts have looked to it as persuasive authority, and some had reached similar rules before 2019. The reasoning has been invoked in disputes involving:
- Industrial equipment that requires proprietary replacement components.
- Medical devices used with third-party accessories or consumables.
- Vehicles and trailers configured with aftermarket equipment.
- Software-dependent products whose hazards arise when integrated with third-party code.
In each, the key factual questions mirror the Court's: was the added part necessary to the product's function, did the manufacturer know of the danger, and would users have understood the risk? Develop those facts through discovery from the beginning, rather than treating the legal question as one for summary judgment on the pleadings.
Building the Record Under the Three-Part Test
For the first element, gather design documents, specifications, and installation manuals that call for the third-party component. A manual that instructs the user to insulate with a specified material strongly supports the argument that the part was required. For the second element, look for internal safety studies, industry publications, trade association bulletins, and prior incident reports showing knowledge of the hazard. For the third, consider the sophistication of the user. A warning issue may be weaker where the product was sold to a highly informed buyer, but weaker does not mean absent. In the Navy cases, the government's knowledge did not excuse the manufacturers as a matter of law.
Defendants will argue that the plaintiff must show exposure to a product the defendant made or sold. That requirement remains in many states, and the plaintiff must still establish causation. Identify with specificity how each defendant's product led to the exposure, using work histories, product identification testimony, and co-worker affidavits.
Practical Strategy
Plead alternative theories. If the claim fits the DeVries framework, allege a failure to warn about the integrated product's hazards and cite the manufacturer's own specifications. Also plead standard design and warning defects, and consider negligence theories tied to the manufacturer's knowledge. Where state law is unsettled, brief the court on how other jurisdictions have treated the question, and show that the facts satisfy the narrower test as well as the broader one.
For defendants, the case offers a path to avoid liability for truly independent third-party components. For plaintiffs, it supplies a route to hold equipment makers responsible when their designs depended on the hazardous material. Settlement values for these claims are heavily influenced by that line, so evaluate each defendant on the specific facts. Related developments in product-based claims are collected in our product liability category, and broader decisions shaping settlement posture appear in our case law and settlements category.
Takeaways
- DeVries is maritime law, but its foreseeability test is persuasive in many states.
- The manufacturer owes a duty to warn when its product requires the hazardous part and the danger is foreseeable.
- Use manuals, specifications, and internal safety documents to prove each element.
- Plead alternative theories and brief the range of state authority.