MESOTHELIOMA | 2026-10-14

The “Bare Metal” Defense in Asbestos Cases: When a Manufacturer Is Liable for Asbestos in Parts It Did Not Make, and What DeVries Decided

A pump or valve manufacturer sold its product “bare metal,” but it required asbestos gaskets and insulation to work, and the worker who replaced those parts for decades developed mesothelioma. Is the manufacturer liable for asbestos it did not make or sell? The bare-metal defense says no — but maritime law and California law both recognize important limits, and the Supreme Court’s DeVries decision reshaped the question.

Many asbestos victims were exposed not to a single asbestos product but to asbestos-containing components — gaskets, packing, insulation, and friction parts — used with equipment like pumps, valves, turbines, and boilers. Often the equipment itself was made of “ bare metal ” and the asbestos parts w

Asbestos exposure often came not from a slab of asbestos but from the routine maintenance of industrial equipment: unbolting and scraping old asbestos gaskets, cutting and removing asbestos insulation, and replacing asbestos packing and friction components. The equipment — a pump, a valve, a turbine — may have been durable metal that lasted decades, while the asbestos parts were consumable and replaced many times, frequently with parts made by other companies. This structure creates a hard question of product-liability law: who is responsible for the asbestos a worker breathed while servicing the equipment? This article explains the competing doctrines and how they apply.

What the “Bare Metal” Defense Argues

The bare-metal defense is the equipment manufacturer’s argument that it is not liable for asbestos-containing parts that it did not manufacture, sell, or supply — even if its equipment used such parts. In its strongest form, the defense contends that a pump or valve maker’s duty extends only to the product it actually placed in the stream of commerce (the bare metal), and not to replacement gaskets, packing, or insulation made and sold by third parties and later installed on or around the equipment. Plaintiffs respond that the equipment was designed to require asbestos components, that the manufacturer knew its product would be used with asbestos and that servicing it would release asbestos dust, and that the manufacturer should therefore bear a duty to warn of that foreseeable hazard. Courts have split on how far the defense reaches, and the answer turns on the governing law and the specific facts about what the manufacturer knew and required.

Why Maritime Law Matters: Navy Ships and Asbestos

A large share of asbestos exposure in the United States occurred aboard Navy ships, where sailors and shipyard workers serviced vast arrays of asbestos-insulated equipment in engine and boiler rooms. Claims arising from exposure aboard vessels on navigable waters are frequently governed by federal maritime law rather than state law. Because the bare-metal question arose so often in Navy cases, and because federal courts had divided over it, the issue reached the U.S. Supreme Court in a maritime case, making the maritime rule especially important for the many California veterans and shipyard workers exposed to asbestos in naval service.

Air & Liquid Systems Corp. v. DeVries: The Supreme Court’s Rule

In Air & Liquid Systems Corp. v. DeVries (2019) 139 S. Ct. 986, the Supreme Court resolved the bare-metal question for maritime law. The Court rejected the most manufacturer-friendly version of the bare-metal defense and adopted a middle approach: in the maritime tort context, a manufacturer of a product has a duty to warn when (1) its product requires incorporation of a part (such as asbestos insulation or gaskets), (2) the manufacturer knows or has reason to know that the integrated product is likely to be dangerous for its intended uses, and (3) the manufacturer has no reason to believe that the product’s users will realize that danger. The Court reasoned that a manufacturer that requires a dangerous part for its product to function, and knows the combination will be used and will be hazardous, is in a position to warn and should do so — rejecting the rule that would relieve such a manufacturer of any duty simply because a third party made the asbestos part. DeVries thus established a duty-to-warn standard, not a design-defect or manufacturing standard, grounded in the equipment maker’s knowledge and the fact that its product required the hazardous component. For maritime asbestos claims — including many Navy cases — DeVries is now the controlling framework.

The Limits of DeVries

DeVries is a duty-to-warn rule with defined boundaries. The duty arises only where the manufacturer’s product required the asbestos part (not merely where asbestos could optionally be used), where the manufacturer knew or had reason to know of the danger of the integrated product, and where users were not expected to recognize the danger themselves. It does not make equipment makers automatically liable for every third-party asbestos part; the plaintiff must fit the facts within the three-part standard. The Court also confined its holding to the maritime context, leaving the treatment of the bare-metal question under state law to the states. This means the governing-law question — maritime or California — is a threshold issue that can determine which standard applies, and litigants must analyze where and how the exposure occurred to decide which framework governs.

California’s Approach to Component and Replacement-Part Liability

Outside maritime law, California applies its own product-liability principles to the bare-metal problem. California courts have generally held that a manufacturer is not liable in strict liability or negligence for harm caused by asbestos products that it did not manufacture or supply, even if its equipment was used with such products — a result consistent with the component-parts and no-duty principles the California Supreme Court applied in the asbestos context in O’Neil v. Crane Co. (2012) 53 Cal.4th 335. O’Neil held that a manufacturer of a product (there, valves and pumps) is not liable for injuries caused by asbestos-containing replacement parts and external insulation made and supplied by others, unless the manufacturer’s own product contributed substantially to the harm or the manufacturer participated substantially in creating the harmful combined use. California thus recognizes a version of the bare-metal limitation, subject to exceptions where the defendant’s own product was itself a substantial factor — for example, where the manufacturer supplied the asbestos component, specified it, or its product necessarily released asbestos from its own original components. The California analysis therefore focuses closely on what the defendant’s own product did and required.

Maritime Versus California: Why the Choice of Law Is Decisive

The two frameworks can produce different outcomes on similar facts, which makes the choice-of-law determination critical. Under DeVries, a maritime plaintiff can reach an equipment manufacturer on a duty-to-warn theory where the product required an asbestos part and the maker knew of the danger — even though the asbestos part came from a third party. Under O’Neil, a California plaintiff generally cannot hold the equipment maker liable for third-party replacement parts and external insulation unless the manufacturer’s own product was a substantial factor or it participated substantially in the harmful combination. A plaintiff exposed aboard a Navy vessel may therefore have a maritime claim governed by DeVries, while the same kind of exposure in a land-based California facility may be governed by O’Neil. Determining whether maritime law applies — which turns on the situs of the exposure and its connection to maritime activity — is thus one of the most consequential early decisions in these cases, and it must be analyzed carefully against the facts of each exposure.

Identifying the Right Defendants

Because of these doctrines, a successful asbestos case built around equipment exposure focuses on identifying the defendants actually responsible for the asbestos the plaintiff breathed. These may include the manufacturers and suppliers of the asbestos components themselves (the gasket, packing, and insulation makers), the equipment manufacturers where DeVries or the O’Neil exceptions make them liable, and other entities in the chain. Many original asbestos-component manufacturers have gone through bankruptcy and established asbestos bankruptcy trusts to pay claims, so recovery often involves both solvent defendants and trust claims. Mapping the plaintiff’s exposure — which equipment, which components, who made them, and under which law — is the core of building a case that reaches every responsible party rather than being defeated by a bare-metal defense.

Overlap With the Government-Contractor and Sophisticated-User Defenses

Equipment makers sued in Navy and industrial asbestos cases frequently raise additional defenses that interact with the bare-metal question. The government-contractor defense (from Boyle v. United Technologies Corp. (1988) 487 U.S. 500) can shield a manufacturer that built equipment to precise military specifications, including specifications that dictated the use of asbestos and controlled the warnings, where the government knew as much as or more than the manufacturer about the hazard. The sophisticated-user and sophisticated-intermediary doctrines (reflected in California in Johnson v. American Standard, Inc. (2008) 43 Cal.4th 56) can limit a duty to warn where the end user or an intermediary (such as the Navy) already knew or should have known of the hazard. These defenses do not automatically defeat a claim — they turn on detailed facts about what the government specified, what each party knew, and when — but they frequently appear alongside the bare-metal defense in equipment cases, and a plaintiff must be prepared to meet all of them. The interplay means that the same case can involve the DeVries duty-to-warn analysis, the O’Neil component-part analysis, and these knowledge-based defenses simultaneously, making careful factual development essential.

What Evidence Establishes the Manufacturer’s Knowledge

Under both DeVries and the O’Neil exceptions, the equipment maker’s knowledge that its product required asbestos and that servicing it would release a hazard is often the decisive fact. The evidence that establishes this includes the manufacturer’s own technical manuals and maintenance instructions (which frequently directed the use of asbestos gaskets, packing, and insulation and described their replacement), engineering specifications showing the product was designed to be used with asbestos components, historical industry and corporate knowledge of asbestos hazards, and correspondence or internal documents reflecting what the manufacturer knew and when. Where a manufacturer’s own manuals told workers to remove and replace asbestos insulation or gaskets, that is powerful evidence that the product required the hazardous component and that the maker knew servicing it would expose workers — exactly the showing DeVries requires. Assembling this documentary record about the specific equipment at issue is central to overcoming a bare-metal defense, because it converts the abstract legal standard into concrete proof that the manufacturer knew the danger and was positioned to warn.

Proving the Case Under Either Standard

Whatever framework applies, the plaintiff must still prove exposure and causation. Under California law, that means the Lineaweaver exposure framework and the Rutherford substantial-factor standard — showing the frequency, regularity, and proximity of exposure to a defendant’s product and that it was a substantial factor in the aggregate dose. Under maritime law, the plaintiff must fit the equipment maker within the DeVries duty-to-warn elements and prove the exposure and causation the tort requires. In both settings, the evidence is built from the plaintiff’s detailed work history, co-worker testimony about the equipment and components used, and expert testimony tying the exposures to the disease. The legal framework determines which defendants are reachable; the factual proof determines whether the case against each one succeeds. Because a single worker’s exposure history often spans both shipboard and land-based settings over a long career, a thorough case may apply the DeVries framework to some exposures and the O’Neil framework to others, pursuing each defendant under the standard that governs the exposure giving rise to liability against it. Getting that mapping right — which exposure, under which law, against which defendant — is what allows a plaintiff to hold the full set of responsible parties accountable rather than losing winnable claims to a bare-metal defense that does not actually apply on the facts.

How Trembach Law Firm Helps

Our firm represents California mesothelioma and asbestos-disease victims whose exposure came from servicing asbestos-dependent equipment. We analyze whether maritime law (and DeVries) or California law (and O’Neil) governs each exposure, identify the component and equipment manufacturers who can be held liable under the applicable standard, pursue the available asbestos bankruptcy trusts, and build the exposure and causation proof the case requires. Because these doctrines can make or break liability against a given defendant, we focus on getting the choice-of-law and defendant-identification analysis right from the start.

Frequently Asked Questions

What is the “bare metal” defense?

It is an equipment manufacturer’s argument that it is not liable for asbestos-containing parts — gaskets, packing, insulation — that it did not make, sell, or supply, even though its “bare metal” product was used with those parts. Whether the defense succeeds depends on the governing law and on what the manufacturer knew and required.

What did Air & Liquid Systems v. DeVries decide?

In DeVries (2019) 139 S. Ct. 986, the Supreme Court held that, in maritime law, a manufacturer has a duty to warn when its product requires incorporation of a dangerous part (like asbestos), the manufacturer knows or has reason to know the integrated product is likely dangerous, and it has no reason to believe users will realize the danger. It rejected the broadest bare-metal defense in the maritime context.

Why does maritime law come up in asbestos cases?

Because a great deal of asbestos exposure occurred aboard Navy ships, where workers serviced asbestos-insulated equipment. Claims from exposure aboard vessels on navigable waters are often governed by federal maritime law rather than state law, which is why the DeVries maritime rule matters so much to veterans and shipyard workers.

How does California law treat the bare-metal question?

Under O’Neil v. Crane Co. (2012) 53 Cal.4th 335, a California equipment manufacturer generally is not liable for asbestos in replacement parts and external insulation made and supplied by others, unless its own product was a substantial factor in causing the harm or it participated substantially in the harmful combined use. California recognizes a bare-metal limitation with important exceptions.

Can the outcome differ depending on which law applies?

Yes. Under DeVries (maritime), an equipment maker can owe a duty to warn where its product required an asbestos part and it knew of the danger. Under O’Neil (California), the maker generally is not liable for third-party replacement parts absent a substantial-factor exception. The same kind of exposure can lead to different results, so determining whether maritime law applies is critical.

Who can I sue if the equipment maker isn’t liable?

Often the manufacturers and suppliers of the asbestos components themselves — the gasket, packing, and insulation makers — and, where DeVries or the O’Neil exceptions apply, the equipment makers. Many original asbestos-component manufacturers established asbestos bankruptcy trusts, so recovery may combine solvent defendants and trust claims.

Do I still have to prove exposure and causation?

Yes. Under California law you must prove exposure under the Lineaweaver frequency-regularity-proximity framework and causation under Rutherford’s substantial-factor standard. Under maritime law you must fit the equipment maker within the DeVries duty-to-warn elements and prove exposure and causation. The legal framework determines who is reachable; the factual proof decides each claim.

I serviced pumps and valves in the Navy and have mesothelioma. Do I have a case?

Possibly a strong one. Navy equipment exposure often falls under maritime law and DeVries, which can reach equipment makers whose products required asbestos parts, and you may also have claims against component makers and bankruptcy trusts. The exposure history and choice-of-law analysis are key. Call Trembach Law Firm at (213) 645-2246 for a free, confidential evaluation.

Talk to a California Mesothelioma Lawyer About Equipment Exposure

When mesothelioma traces to servicing asbestos-dependent equipment, whether the maker is liable turns on the bare-metal defense, the DeVries maritime duty-to-warn rule, and California’s O’Neil component-part principles. Trembach Law Firm, led by Anatolii Trembach (LL.M.; admitted in California), gets the choice-of-law and defendant analysis right and pursues every responsible party. Call (213) 645-2246 for a confidential consultation.

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

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