Opinion
This сase involves the limits of a manufacturer’s duty to prevent foreseeable harm related to its product: When is a product manufacturer liable for injuries caused by adjacent products or replacement parts that were made by others and used in conjunction with the defendant’s product? We hold that a product manufacturer may not be held liable in strict liability or negligence for harm caused by another manufacturer’s product unless the defendant’s own product contributed substantially to the harm, or the defendant participated substantially in creating a harmful combined use of the products.
Defendants Crane Co. (Crane) and Warren Pumps LLC (Warren) made valves and pumps used in Navy warships. They were sued here for a wrongful death allegedly caused by asbestos released from external insulation and internal gaskets and packing, all of which were made by third parties and added to the pumps and valves after sale. It is undisputed that defendants never manufactured or sold any of the asbestos-containing materials to which plaintiffs’ decedent was exposed. Nevertheless, plaintiffs claim defendants should be held strictly liable and negligent because it was foreseeable workers would be exposed to and harmed by the asbestos in replacement parts and prоducts used in conjunction with their pumps and valves.
Recognizing plaintiffs’ claims would represent an unprecedented expansion of strict products liability. We decline to do so. California law has long provided that manufacturers, distributors, and retailers have a duty to ensure the safety of their products and will be held strictly liable for injuries caused by a defect in their products. Yet, we have never held that these responsibilities extend to preventing injuries caused by other products that might foreseeably be used in conjunction with a defendant’s product. Nor have we *343 held that manufacturers must warn about potential hazards in replacement parts made by others when, as here, the dangerous feature of these parts was not integral to the product’s design. The broad rule plaintiffs urge would not further the purposes of strict liability. Nor would public policy be served by requiring manufacturers to warn about the dangerous propensities of products they do not design, make, or sell.
BACKGROUND
I. Defendants’ Pump and Valve Products on Navy Warships
During World War II, defendants sold parts to the United States Navy for use in the steam propulsion systems of warships. These propulsion systems were vast and complex. Massive boilers generated steam from seawater. The steam flowed through a maze of interconnected pipes to power the ship’s engines and providе energy for use throughout the vessel. A single ship contained several miles of piping. Because the steam flowing through this system was extremely hot and highly pressurized, the pipes and attached components required insulation to prevent heat loss and protect against accidental bums. Navy specifications required the use of asbestos-containing insulation on all external surfaces of the steam propulsion systems. Asbestos insulation was also used as an internal sealant within gaskets and other components of the propulsion system. The Navy preferred asbestos over other types of insulating materials because it was lightweight, strong, and effective. Indeed, asbestos was considered to be such an important resource that a 1942 federal regulation ordered its conservation for the war effort. (Conservation order No. M-123, 7 Fed.Reg. 2472 (Mar. 31, 1942).) Plaintiffs’ expert admitted there was no acceptable substitute for asbestos until at least the late 1960’s. Warships could not have been built without it.
The Navy’s Bureau of Ships oversaw the design and construction of warships. Naval engineers created specifications that provided detailed design, material, and performance requirements for equipment to be used on board. Equipment that did not conform with the Navy’s specificatiоns was rejected. Product manufacturers were required to comply with naval specifications, including those mandating the use of asbestos.
Crane produced valves for Navy ships according to these strict military specifications. The steam propulsion system in a typical warship included hundreds of valves of different sizes and functions. In general, valves controlled the flow of steam from one point to another through the system. Packing materials inside valves were used as sealants, to protect against leakage of high-pressure steam or liquids. Although cotton packing was sometimes used for colder temperature applications, the majority of packing *344 used on Navy ships contained asbestos. Gaskets were also used inside the valves to seal the joints between metal surfaces. Although some gaskets were made of metal, the gaskets used in valves, flanges, or pump casings generally contained asbestos. During the early 1940’s, Navy specifications required that the internal gaskets and packing materials in valves contain asbestos. At that time, asbestos was the only insulating material that could withstand the extremely high temperatures and pressures produced by a warship’s steam propulsion system. Following mandated Navy specifications, Crane used asbestos in its vаlves and packing. However, no evidence was presented that asbestos, as opposed to some other type of insulation material, was needed in order for the valves to function properly. Indeed, Crane made some valves of corrugated iron, which contained no asbestos. Crane did not manufacture the asbestos packing or gaskets used in its valves. It purchased these components from Navy-approved vendors.
Warren supplied pumps. Navy ships contained hundreds of pumps used for various purposes. In the steam propulsion system of a warship, pumps moved liquids and condensed steam. Like Crane, Warren built its pumps for specific ships in accordance with stringent naval specifications. Most of these pumps had internal gaskets and packing that contained asbestos. 1 One Warren pump also had asbestos insulation around a valve stem, but it was covered with a layer of sheet metal. The pumps were not made or shipped with external insulation. As with Crane’s valves, no evidence was presented that Warren’s pumps required the use of internal components made with asbestos in order to operate.
Once the parts were received, shipbuilders integrated them into a complex steam propulsion system. Pumps and vаlves were connected to other components, such as boilers and piping, with asbestos-containing flange gaskets. Neither Crane nor Warren produced these flange gaskets. All metal components of the steam propulsion system, including miles of piping, were then covered in a layer of asbestos insulation. This insulation was made and sold by other companies, most notably Johns-Manville. Neither Crane nor Warren produced the external insulation. The valves and pumps did not need external insulation in order to function.
The gaskets and packing inside Crane’s valves and Warren’s pumps were replaced during routine maintenance. No evidence was presented that Warren ever made or sold these replacement parts. Crane did not manufacture asbestos packing or gaskets. Although Crane did at one time sell replacement packing and gaskets for use in maintaining and repairing its valves, these *345 products were generally shipped under the label of the packing or gasket manufacturer and often shipped directly from that manufacturer to the customer. There was no evidence that the Navy ever purchased replacement gaskets or packing materials from Crane.
II. Plaintiffs Exposure to Asbestos
Patrick O’Neil served on the USS Oriskany (Oriskany) from 1965 to 1967. The Oriskany was a large “Essex class” aircraft carrier carrying up to 4,000 crewmembers. The ship was authorized in 1942, launched in 1945, and commissioned to active service in 1950. Crane and Warren supplied equipment for the Oriskany’’ s steam propulsion system in 1943 or earlier, at least 20 years before O’Neil worked aboard the ship.
Among his other duties on the
Oriskany,
O’Neil supervised the enlisted men who repaired equipment in the engine and boiler rooms. This work exposed him to airborne asbestos fibers. Asbestos-containing products are not dangerous when intact. The health hazard arises when the products are cut or damaged, releasing asbestos fibers that can be inhaled. (See
San Francisco Unified School Dist. v. W.R. Grace & Co.
(1995)
To the extent O’Neil was exposed to dust generated during work on pumps and valves, no evidence was presented that any of the asbestos-containing dust came from a product made by Crane or Warren. Neither company manufactured or sold the external insulation or flange gaskets that repairmen removed. Although Crane’s valves and Warren’s pumps contained internal asbestos-containing gaskets and packing when the Oriskany was built, these original components had been replaced long before O’Neil boarded the ship 20 years later. There was no evidence that any of these replacement parts were made by Crane or Warren.
*346 In 2004, nearly 40 years after he worked on the Oriskany, O’Neil developed mesothelioma, a fatal cancer of the lining of the lung caused by asbestos exposure. He died just over a year later, at age 62. In 2006, O’Neil’s family filed a wrongful death complaint raising strict liability and negligence claims against several companies that had allegedly supplied asbestos-containing products to the Navy.
Following the close of evidence, Crane moved for nonsuit on all causes of action. Among other things, Crane argued there was no evidence O’Neil had been exposed to asbestos from any Crane product, and no evidence that any product defect or failure to warn by Crane was a substantial factor in causing O’Neil’s mesothelioma. Warren joined Crane’s motion and also sought nonsuit on the ground that no evidence showed O’Neil had been exposed to any asbestos from the repair or maintenance of a Warren pump. In response, plaintiffs’ counsel argued that even if O’Neil was not exposed to asbestos released from a Crane or Warren product, these manufacturers bore responsibility for his injuries because their products originally included asbestos-containing components, and it was foreseeable that these parts would wear and be replaced with other asbestos-containing components, and that these repair and maintenance procedures would release harmful asbestos dust.
The trial court granted the motions and dismissed all claims against Crane and Warren.
3
The court found there was no evidence defendants’ products were inherently dangerous except for the undisturbed internal asbestos components some contained. Further, although the nonsuit motions did not raise this ground, the court found that the component parts doсtrine shielded defendants from liability because the Navy integrated defendants’ nondefective products into a larger, sophisticated system, and defendants did not control or participate in this integration process. (See
Artiglio v. General Electric Co.
(1998)
The Court of Appeal held that the component parts defense applies only to manufacturers of “multiuse or fungible products” designed to be altered and incorporated into another product. It then concluded defendants’ products did not meet these requirements. The Court of Appeal also rejected defendants’ argument that they could not be found strictly liable because they did not manufacture or supply the asbestos-containing products that caused O’Neil’s mesothelioma. The court announced a broad definition of strict products liability: “[A] manufacturer is liable in strict liability for the dangerous components of its products, and for dangerous products with which its *347 product will necessarily be used.” Even though it was replacement gaskets and packing that caused O’Neil’s disease, the court concluded these replacement parts were “no different” from the asbestos-containing components originally included in defendants’ products. The court remarked, “If respondents had warned the hypothetical original user, or protected that person by avoiding defective design, subsequent users, too, would have been protected.” The Court of Appeal asserted defendants’ products were defectively designed “because they required asbestos packing and insulation.” This factual assertion is unsupported by the record. Trial evidence established that the requirement for asbestos derived from military specifications, not from any inherent aspect of defendants’ pump and valve designs. 4
We granted review and now reverse.
DISCUSSION
In reviewing a judgment of nonsuit, “we must view the facts in the light most favorable to the plaintiff. ‘[C]ourts traditionally have taken a very restrictive view of the circumstances under which nonsuit is proper. The rule is that a trial court may not grant a defendant’s motion for nonsuit if plaintiff’s evidence would support a jury verdict in plaintiff’s favor. [Citations.] [1] In determining whether plaintiff’s evidence is sufficient, the court may not weigh the evidence or consider the credibility of witnesses. Instead, the evidence most favorable to plaintiff must be accepted as true and conflicting evidence must be disregarded. The court must give “to the plaintiff[’s] evidence all the value to which it is legally entitled, . . . indulging every legitimate inference which may be drawn from the evidence in plaintiff[’s] favor ....”’ [Citation.] The same rule applies on appeal from the grаnt of a nonsuit. [Citation.]”
(Castaneda
v.
Olsher
(2007)
I. Strict Liability
Strict liability has been imposed for three types of product defects: manufacturing defects, design defects, and “ ‘warning defects.’ ”
(Anderson
v.
Owens-Corning Fiberglas Corp.
(1991)
*348 Plaintiffs argue defendants’ products were defective because they included and were used in connection with asbestos-containing parts. They also contend defendants should be held strictly liable for failing to warn O’Neil about the potential health consequences of breathing asbestos dust released from the products used in connection with their pumps and valves. These claims lack merit. We conclude that defendants were not strictly liable for O’Neil’s injuries because (a) any design defect in defendants’ products was not a legal cause of injury to O’Neil, and (b) defendants had no duty to warn of risks arising from other manufacturers’ products.
A. No Liability Outside a Defective Product’s Chain of Distribution
From the outset, strict products liability in California has always been premised on harm caused by deficiencies in the defendant’s own product. We first announced the mle in
Greenman v. Yuba Power Products, Inc.
(1963)
Strict liability encompasses all injuries caused by a defective product, even those traceable to a defective component part that was supplied by another.
(Vandermark v. Ford Motor Co., supra,
*349
In
Peterson v. Superior Court
(1995)
In this case, it is undisputed that O’Neil was exposed to no asbestos from a product made by defendants. Although he was exposed to potentially high levels of asbestos dust released from insulation the Navy had applied to the exterior of the pumps and valves, Crane and Warren did not manufacture or sell this external insulation. They did not mandate or advise that it be used with their products. O’Neil was also exposed to asbestos from the replacement gaskets and packing inside the pumps and valves. Yet, uncontroverted evidence established that these internal components were not the original parts supplied by Crane and Warren. They were replacement parts the Navy had purchased from other sources. 5
It is fundamental that the imposition of liability requires a showing that the plaintiff’s injuries were caused by an act of the defendant or an instrumentality under the defendant’s control.
(Sindell
v.
Abbott Laboratories
(1980)
Nor does the record support plaintiffs’ claim that defendants’ products were defective because they were “designed to be used” with asbestos-containing components. The products were designed to meet the Navy’s specifications. Moreover, there was no evidence that defendants’ products required asbestos-containing gaskets or packing in order to function. Plaintiffs’ assertion to the contrary is belied by evidence that defendants made some pumps and valves without asbestos-containing parts. As alternative insulating materials became available, the Navy could have chosen to replace worn gaskets and seals in defendants’ products with parts that did not contain asbestos. Apart from the Navy’s specifications, no evidence showed that the design of defendants’ products required the use of asbestos components, and their mere compatibility for use with such components is not enough to render them defective. 6
Plaintiffs and some amici curiae also suggest that defendants’ products were defective because they became hot during high-temperature applications, and this heat “baked on” the thermal insulation, causing asbestos in the insulation to become “friable.” Friable insulation materials may crumble and release respirable asbestos fibers into the air.
(San Francisco Unified School Dist.
v.
W.R. Grace & Co., supra,
B. No Duty to Warn of Defects in Another Manufacturer’s Product
Plaintiffs also argue that defendants had a duty to warn O’Neil about the hazards of asbestos because the release of asbestos dust from surrounding products was a foreseeable consequence of maintenance work on defendants’ pumps and valves.
1. General Principles
“Generally speaking, manufacturers have a duty to warn consumers about the hazards inherent in their products.
(Anderson
[v.
Owens-Corning Fiberglas Corp.], supra,
In
Garman v. Magic Chef, Inc.
(1981)
The decision in
Powell v. Standard Brands Paint Co.
(1985)
So too here. Crane and Warren gave no warning about the dangers of asbestos in the gaskets and packing originally included in their products. However, O’Neil never encountered these original parts. His exposure to asbestos came from replacement gaskets and packing and external insulation added to defendants’ products long after their installation on the
Oriskany.
There is no dispute that these external and replacement products were made by other manufacturers. “[N]o case law . . . supports the idea that a manufacturer, after selling a completed product to a purchaser, remains under a duty to warn the purchaser of potentially defectivе additional pieces of equipment that the purchaser may or may not use to complement the product bought from the manufacturer.”
(In re Deep Vein Thrombosis
(N.D.Cal. 2005)
*353
Decisions from other jurisdictions are in accord.
Rastelli
v.
Goodyear Tire & Rubber Co.
(1992)
2. Application in the Asbestos Context
a. The Taylor v. Elliott Turbomachinery Co. Decision
In 2009, the First District Court of Appeal addressed the very question presented here. In
Taylor
v.
Elliott Turbomachinery Co. Inc.
(2009)
“First, California law restricts the duty to warn to entities in the chain of distribution of the defective product.”
(Taylor, supra,
Second, in a related holding, the Court of Appeal determined that “in California, a manufacturer has no duty to warn of defects in products supplied by others and used in conjunction with the manufacturer’s product unless the manufacturer’s product itself causes or creates the risk of harm.”
(Taylor, supra,
Third, the
Taylor
court determined that the component parts doctrine provided an alternate basis for concluding the pump and valve manufacturers owed no duty to warn about the dangers of asbestos.
(Taylor, supra,
171 Cal.App.4th at pp. 584-586.) The component parts doctrine provides that the manufacturer of a component part is not liable for injuries caused by the finished product into which the component has been incorporated unless the component itself was defective and caused harm.
(Jimenez
v.
Superior Court
(2002)
b. Out-of-state Decisions
As additional support for its holdings, the Taylor court discussed a pair of asbestos cases from Washington State and a federal case from Ohio. These decisions are instructive.
In
Simonetta
v.
Viad Corp.
(2008)
While
Simonetta
speaks to liability for injuries arising from external insulation, its companion case,
Braaten v. Saberhagen Holdings
(2008)
The
Simonetta
and
Braaten
decisions both discussed
Lindstrom
v.
A-C Product Liability Trust
(6th Cir. 2005)
The issue of liability for replacement parts has also arisen in other types of asbestos cases. In
Ford Motor
v.
Wood
(1998)
Reliance on the “adjacent products” theory of liability was stretched perhaps the farthest in
Macias v. Mine Safety Appliances Co.
(2010)
3. Plaintiffs’ Authorities Are Distinguishable
The Court of Appeal here disagreed with
Taylor
and ignored the out-of-state decisions discussed above. Instead, the court relied on its own prior decision in
Tellez-Cordova
v.
Campbell-Hausfeld/Scott Fetzger Co.
(2004)
*359
In
DeLeon
v.
Commercial Manufacturing & Supply Co.
(1983)
In some respects, DeLeon’s facts resemble those presented here. Like DeLeon, O’Neil suffered a foreseeable injury not from defendant’s product, but from another manufacturer’s product located nearby. An important difference, however, is that the bin manufacturer in DeLeon was heavily involved in creating the dangerous condition that gave rise to the plaintiff’s injury. DeLeon’s injury resulted not from any intrinsic defect in the bin or the line shaft, but in the dangerous proximity of these two products. The bin manufacturer contributed to this dangerous сondition because it designed the bin specifically for use in the particular site where it was located. (DeLeon, supra, 148 Cal.App.3d at pp. 341-342, 345.) The bin’s designer visited the site but “never noticed the shaft overhead, did not know what it was,” and did not investigate to determine whether it presented a safety hazard. (Id. at p. 341.)
The
DeLeon
court itself observed that the case did not pose “a clear-cut legal question of component part liability,” but instead presented “a factual issue of [the manufacturer’s] involvement in design which will permit variations in the applicable rules of law depending upon how the trier of fact determines the extent of [the manufacturer’s] design responsibility.”
(DeLeon, supra,
Plaintiffs’ reliance on
Wright v. Stang Manufacturing Co.
(1997)
Finally, the Court of Appeal below maintained that the result here was controlled by its prior decision in
Tellez-Cordova, supra,
Tellez-Cordova developed lung disease from breathing toxic substances released from metals he cut and sanded and from abrasive discs on the power tools he used.
(Tellez-Cordova, supra,
*361
The facts in
Tellez-Cordova
differed from the present case in two significant respects. First, the power tools in
Tellez-Cordova
could
only
be used in a potentially injury-producing manner. Their sole purpose was to grind metals in a process that inevitably produced harmful dust. In contrast, the normal operation of defendants’ pumps and valves did not inеvitably cause the release of asbestos dust. This is true even if “normal operation” is defined broadly to include the dusty activities of routine repair and maintenance, because the evidence did not establish that defendants’ products needed asbestos-containing components or insulation to function properly. It was the Navy that decided to apply asbestos-containing thermal insulation to defendants’ products and to replace worn gaskets and packing with asbestos-containing components. Second, it was the action of the power tools in
Tellez-Cordova
that
caused
the release of harmful dust, even though the dust itself emanated from another substance.
Tellez-Cordova
is arguably an example of a “case where the combination of one sound product with another sound product creates a dangerous condition about which the manufacturer of each product has a duty to warn [citation].” (Rastelli, supra,
Moreover, as noted, California law does not impose a duty to warn about dangers arising entirely from another manufacturer’s product, even if it is foreseeable that the products will be used together. Were it otherwise, manufacturers of the saws used to cut insulation would become the next targets of asbestos lawsuits. Recognizing a duty to warn was appropriate in
Tellez-Cordova
because there the defendant’s product was intended to be used with another product
for the very activity that created a hazardous situation.
Where the intended use of a product inevitably creates a hazardous situation, it is reasonable to expect the manufacturer to give warnings. Conversely, where thе hazard arises entirely from another product, and the defendant’s product does not create or contribute to that hazard, liability is
*362
not appropriate. We have not required manufacturers to warn about all foreseeable harms that might occur in the vicinity of their products. “From its inception, . . . strict liability has never been, and is not now,
absolute
liability. As has been repeatedly expressed, under strict liability the manufacturer does not thereby become the insurer of the safety of the product’s user. [Citations.]” (D
aly
v.
General Motors Corp., supra,
4. Conclusion
We reaffirm that a product manufacturer generally may not be held strictly liable for harm caused by another manufacturer’s product. The only exceptions to this rule arise when the defendant bears some direct responsibility for the harm, either because the defendant’s own product contributed substantially to the harm (see
Tellez-Cordova, supra,
Plaintiffs here seek to expand these exceptions to make manufacturers strictly liable when it is foreseeable that their products will be used in conjunction with defective products or replacement parts made or sold by someone else. However, the foreseeability of harm, standing alone, is not a sufficient bаsis for imposing strict liability on the manufacturer of a nondefective product, or one whose arguably defective product does not actually cause harm. (Cf.
Peterson v. Superior Court, supra,
10 Cal.4th at pp. 1199-1200 [refusing to extend strict liability to hotel operators based on “[t]he mere circumstance that it was contemplated” that occupants would use potentially defective products installed in their rooms].) Generally, foreseeability is relevant in a strict liability analysis to determine whether injury is likely to result from a potential use or misuse of a product. (See
Daly v. General Motors Corp., supra,
The question whether to apply strict liability in a new setting is largely determined by the policies underlying the doctrine.
(Anderson v.
*363
Owens-Corning Fiberglas Corp., supra,
A contrary rule would require manufacturers to investigate the potential risks of all other products and replacement parts that might foresee-ably be used with their own product and warn about all of these risks. “It does not comport with principles of strict liability to impose on manufacturers the responsibility and costs of becoming experts in other manufacturers’ products.”
(Braaten, supra,
II. No Duty of Care to Prevent Injuries from Another Manufacturer’s Product
Defendants also moved for nonsuit of plaintiffs’ negligence claims. Although the Court of Appeal declined to address these claims, plaintiffs continue to assert negligence as an alternative basis for liability. Because the negligence issue here concerns the scope of defendants’ duty, and the existence of duty is a pure question of law
(Merrill
v.
Navegar, Inc.
(2001) 26
*364
Cal.4th 465, 477 [
“ ‘ “[D]uty” is not an immutable fact of nature “ ‘but only an expression of the sum total of those
considerations of policy
which lead the law to say that the particular plaintiff is entitled to protection.’ ” [Citation.]’ [Citation.]”
(Parsons
v.
Crown Disposal Co.
(1997)
Plaintiffs stress that foreseeability is the critical inquiry in evaluating whether a duty of care is owed. (See
Tarasoff
v.
Regents of University of California
(1976)
Assuming that a manufacturer can “reasonably be expected to foresee the risk of latent disease arising from products supplied by others that may be used with the manufacturer’s product years or decades after the product leaves the manufacturer’s control” (Taylor, supra, 171 Cal.App.4th at *365 p. 594), 12 we nevertheless conclude strong policy considerations counsel against imposing a duty of care on pump and valve manufacturers to prevent asbestos-related disease.
The factors set forth in
Rowland
v.
Christian, supra,
In short, expansion of the duty of care as urged here would impose an obligation to compensate on those whose products caused the plaintiffs no harm. To do so would exceed the boundaries established over decades of product liability law. “ ‘[S]ocial policy must at some point intervene to
*366
delimit liability’ even for foreseeable injury . . ..”
(Parsons v. Crown Disposal Co., supra,
Because defendants owed O’Neil no duty of care, the trial court properly entered nonsuit on plaintiffs’ negligence claims.
DISPOSITION
The decision of the Court of Appeal is reversed, and the case is remanded for entry of a judgment of nonsuit in favor of defendants.
Cantil-Sakauye, C. J., Kennard, J., Baxter, J., Werdegar, J., Chin, J., and Liu, J., concurred.
Notes
However, pumps that were not used for high-temperature applications often had no asbestos-containing parts. For example, some pumps contained gaskets made of plant fiber, with plastic packing.
The Navy is immune from liability for injuries arising from the use of asbestos in shipyards and warships.
(Collins v. Plant Insulation Co.
(2010)
The court also dismissed claims against Yarway Corporation, a valve manufacturer that had moved for nonsuit on the same grounds asserted by Crane and Warren. In January 2009, plaintiffs dismissed their appeal against Yarway.
Defendants raised this issue in a petition for rehearing, which was denied.
Although Crane did at one time sell replaсement gaskets and packing, there is no evidence the Navy ever purchased these replacement parts from Crane or installed them on the Oriskany.
A stronger argument for liability might be made in the case of a product that required the use of a defective part in order to operate. In such a case, the finished product would inevitably incorporate a defect. One could argue that replacement of the original defective part with an identically defective one supplied by another manufacturer would not break the chain of causation. Similarly, if the product manufacturer specified or required the use of a defective replacement part, a stronger case could be made that the manufacturer’s failure to warn was a proximate cause of resulting injury. In both contexts, however, the policy rationales against imposing liability on a manufacturer for a defective part it did not produce or supply would remain. (See post, at pp. 362-363.) These difficult questions are not presented in the case before us, and we express no opinion on their appropriate resolution.
Although the Powell court expounded at length on the legal and policy rationales for limiting a manufacturer’s duty to warn to harms arising from its own product, and endеavored to describe the limited circumstances under which liability for failure to warn could extend to injuries caused by a “genetically identical” product with the same risks as the manufacturer’s product (Powell v. Standard Brands Paint Co., supra, 166 Cal.App.3d at pp. 363-366), the court did not decide whether such liability could be imposed in the case before it because this theory had not been pleaded in the complaint. (Id. at pp. 365-366.)
In In re Deep Vein Thrombosis, passengers who allegedly developed injuries from defective airline seating sued the airplane manufacturer, Boeing Company. The evidence showed that Boeing manufactured planes with no installed seating; instead, airlines purchased *353 seating from a separate manufacturer and installed the seats without Boeing’s involvement. (In re Deep Vein Thrombosis, supra, 356 F.Supp.2d at pp. 1058-1059.) The district court held Boeing had no duty to warn the airlines or passengers about the risk of injury from unsafe seating designs. (Id. at pp. 1067-1069.)
Crane and Warren were among the defendants.
(Taylor, supra,
In so finding, the court rejected an argument that the component parts doctrine shields only manufacturers of “ ‘fungible, multi-use components.’ ” (Taylor, supra, 111 Cal.App.4th at p. 584.) We express no opinion on whether the pumps and valves used in marine propulsion systems are “fungible,” or whether the component parts defense is limited to fungible products.
Contrary to the plaintiffs’ assertion on appeal, the case had not been tried or submitted to the jury on the theory that Ford had a duty to warn about hazards in replacement brakes and clutches. (Ford Motor v. Wood, supra, 703 A.2d at pp. 1330-1331.) The court observed that, even assuming the issue had been properly preserved, “we would not find liability under that theory as a matter of law.” (Id. at p. 1331.)
But see
Cabral v. Ralphs Grocery Co.
(2011)
Indeed, there can be little doubt that defendants’ conduct was “of high social utility.”
(Parsons v. Crown Disposal Co., supra,
