
132 Cal.Rptr.2d 819 (2003)
107 Cal.App.4th 1211
Augusta FERRIS et al., Plaintiffs and Appellants,
v.
GATKE CORPORATION, Defendant and Respondent.
No. A093413.
Court of Appeal, First District, Division Four.
March 28, 2003.
Review Denied July 9, 2003.
*821 Alan Richard Brayton, Brayton, Purcell, Curtis & Geagan, Novato, CA, for Plaintiff-Appellant.
Sedgwick, Deter, Moran & Arnold, Frederick, D. Baker, Charles T. Sheldon, Katharine Demgen, Charles P. Murrin; Bennett, Samuelsen, Reynolds & Allard, Richard Reynolds, Frederick W. Gatt and Don Schaefer, for Defendant-Respondent.
Gayle Irene Jenkins for Thelen Reid & Priest LLP, Los Angeles, CA, as Amicus Curiae on behalf of Respondent.
*820 SEPULVEDA, J.
Does Sindell's burden-shifting "market share" theory of tort liability apply in litigation seeking recovery for personal injury and wrongful death from inhalation of asbestos fibers? (Sindell v. Abbott Laboratories (1980) 26 Cal.3d 588, 163 Cal.Rptr. 132, 607 P.2d 924 (Sindell).) As will appear, while the answer to that general proposition has been the subject of uncertainty, we conclude the circumstances presented by this record make it unnecessary for us to resolve the issue vel non. It is sufficient, we decide, that assuming Sindell relief may under some circumstances be available to plaintiffs in asbestos-related tort litigation, the record in this appeal fails to furnish the requisites necessary to establish that species of group tort liability. In light of that conclusion, we hold the superior court did not err here when it barred plaintiffs from pursuing Sindell relief at trial. For not unrelated reasons, we also conclude the trial court was correct when it granted a defense motion for non-suit on plaintiffs' civil conspiracy claims. Given these dispositions, we will affirm the ensuing judgment for defendant from which this appeal is taken.

FACTUAL AND PROCEDURAL BACKGROUND
Asserting he had been employed in naval shipyards and around other sources of asbestos exposure during his working life and regularly had replaced the friction brake shoes on his own and his neighbors' automobiles for close to 40 years, in December 1998, Harley Ferris and his wife Augusta filed suit for damages in tort against numerous manufacturers, suppliers, and distributors of asbestos, including manufacturers of friction brake products containing that mineral. The original complaint sought damages for personal injury and loss of consortium on theories of negligence, strict liability, fraud and deceit, and civil conspiracy. Not long thereafter, Mr. Ferris died from the effects of mesothelioma, an incurable pulmonary cancer associated with and thought to be caused by inhalation of asbestos particles. Joined by the Ferrises' two sons, Augusta pressed on with the lawsuit, amending the complaint to plead an additional cause of action for wrongful death.
*822 The cause was called for trial on August 8, 2000. The defense filed an in limine motion to exclude evidence supporting a market share theory of liability, contending plaintiffs had not and could not establish that friction brake products containing asbestos were fungible, and had not and could not join defendants with a substantial share of the national friction products market. This motion was denied by the trial court without prejudice to its renewal following a hearing under Evidence Code section 402. Following such a hearing on August 22, 2000, defense motions in limine to exclude evidence supporting a theory of market share liability were renewed. At a hearing held on August 31, 2000, the trial court granted those motions. Somewhat later in the trial court proceedings, on September 7, 2000, the court granted Gatke Corporation's motion for nonsuit on plaintiffs' claims in negligence and strict products liability, as well as their civil conspiracy claims, founded on negligence and products liability. After judgment for defendant was entered on November 17, 2000, this timely appeal followed.

ANALYSIS

1. On this record, the trial court did not err in barring plaintiffs from pursuing Sindell relief.

In Sindell, supra, 26 Cal.3d 588, 163 Cal.Rptr. 132, 607 P.2d 924, the plaintiff sought to impose tort liability on the defendant pharmaceutical manufacturers, alleging that while pregnant, her mother (along with thousands of other pregnant American women between 1941 and 1971) was given a synthetic compound of the female hormone estrogen known as diethylstilbestrol or DES, as a miscarriage preventative. (Id. at p. 593, 163 Cal.Rptr. 132, 607 P.2d 924.) It was later determined that DES could cause cancerous vaginal and cervical growths in women exposed to it before birth by their mothers taking the drug during pregnancy. Judith Sindell eventually developed a bladder malignancy and related medical problems that, she asserted, were caused by her mother's ingestion of DES. Contending DES was produced from a common and mutually agreed upon formula "as a fungible drug interchangeable with other brands of the same product," and that the defendant manufacturers "collaborated in marketing, promoting and testing the drug, relied upon each other's tests, and adhered to an industry-wide safety standard," the plaintiff contended the defendant manufacturers were jointly and severally liable to her "because they acted in concert, on the basis of express and implied agreements, and in reliance upon and ratification and exploitation of each other's testing and marketing methods." (Id. at pp. 594-595, 163 Cal.Rptr. 132, 607 P.2d 924.)
Although it rejected the plaintiffs group liability theories denominated "alternative liability," "concert of action," and "industry-wide" or "enterprise liability" (Sindell, supra, 26 Cal.3d 588 at pp. 598, 603, 163 Cal.Rptr. 132, 607 P.2d 924), Justice Mosk's opinion for the majority crafted a burden-shifting approach requiring the defendant manufacturers to prove they did not produce the DES Ms. Sindell's mother had ingested, or be liable to the plaintiff in proportion to their shares of the DES national market. This novel theory of group liabilitythe so-called market share theory[1]was derived by the *823 Sindell court from another celebrated California Supreme Court decision, Summers v. Tice (1948) 33 Cal.2d 80, 199 P.2d 1 (Summers). (Sindell, supra, 26 Cal.3d at p. 598, 163 Cal.Rptr. 132, 607 P.2d 924.) In Summers, the court had held that a plaintiff, struck in the eye by birdshot when two hunters each negligently fired their shotguns in his direction, could recover damages from either or both. Despite the fact that only one of the defendant hunters could have fired the birdshot that struck the plaintiff, both were negligent wrongdoers and it would be unfair, Justice Carter reasoned for a unanimous court, to deprive the injured plaintiff of a remedy solely because it could not be determined which of the negligent defendants had fired the birdshot that actually struck him. (Summers, supra, 33 Cal.2d 80 at p. 86, 199 P.2d 1.) In these all-but-unique circumstances, the Supreme Court's Summers opinion dispensed with the requirement that a tort plaintiff must establish causation as a necessary condition to a defendant's liability.
Nearly a decade after Sindell, this court decided Mullen, supra, 200 Cal.App.3d 250, 246 Cal.Rptr. 32. There, three homeowners filed a statewide class action suit against numerous manufacturers of asbestos products used in residential housing construction, alleging personal injury and property damage to their homes from both the use of such products and the cost of its removal. Alleging the asbestos products were "`functionally interchangeable'" and that no testing procedures existed "`to identify which defendant made a particular asbestos-containing product,'" the complaint sought to impose liability on defendants under a Sindell market share theory. (Id. at p. 253, 246 Cal.Rptr. 32.) General demurrers without leave to amend were sustained by the trial court; plaintiffs appealed and this court affirmed.
"The briefest consideration," wrote Justice Poché, "demonstrates numerous inherent differences between DES and asbestos." (Mullen, supra, 200 Cal.App.3d 250 at p. 255, 246 Cal.Rptr. 32.) Quoting from a Florida Supreme Court decision, the Mullen court observed that "`DES was produced by hundreds of companies pursuant to one formula. As a result, all DES had identical physical properties and chemical compositions and, consequently, all DES prescribed to pregnant women created the same risk of harm.... [11] Asbestos products, on the other hand, have widely divergent toxicities ... caused by a combination of factors, including: the specific type of asbestos fiber incorporated into the product; the physical properties of the product itself; and the percentage of asbestos used in the product. There are six different asbestos silicates used in industrial applications and each presents a distinct degree of toxicity in accordance with the shape and aerodynamics of the individual fibers. Further, it has been established that the geographical origin of the mineral can affect the substance's harmful effects." (Id. at pp. 255-256, 246 Cal.Rptr. 32, quoting Celotex Corp. v. Copeland (Fla.1985) 471 So.2d 533, 537, 538 italics added by Celotex Corp.)
*824 Unlike Sindell where the Supreme Court "took pains to establish that it was dealing with `fungible goods' ... produced `from an identical formula'" (Mullen, supra, 200 Cal.App.3d at p. 255, 246 Cal. Rptr. 32), our Mullen opinion observed that asbestos "is a generic designation possessing a rainbow-like diversity and a bewildering array of potential uses.... `Because `asbestos is not a "product," but rather a generic name for a family of minerals ... employed in a myriad of uses,'" the court reasoned, "`the unavoidable conclusion is that plaintiffs are attacking an entire industry, not seeking ... damages caused by a single fungible product carr[y]ing with it a singular risk factor.' In light of these circumstances, the prerequisite of fungibility has not been demonstrated. Plaintiffs have therefore failed to state a cause of action for market share liability." (Id. at pp. 256-257, 246 Cal.Rptr. 32.) "We thus align California," the Mullen court concluded, "the progenitor of the market share theory of liability, with the great majority of jurisdictions which have declined to extend it to the field of asbestos-related injuries. [Citations.]" (Id. at p. 257, 246 Cal.Rptr. 32.)
Four years after Mullen was decided, this court decided Wheeler v. Raybestos-Manhattan (1992) 8 Cal.App.4th 1152, 11 Cal.Rptr.2d 109 (Wheeler). There, five plaintiffs who had worked around and been exposed to asbestos dust from automotive friction brake products filed personal injury damages actions against three asbestos manufacturers in San Francisco Superior Court. As with all other asbestos personal injury litigation filed in San Francisco, plaintiffs' consolidated actions were subject to that court's general order 21, providing "the theory of market share liability articulated in Sindell ... is inapplicable to asbestos cases." (Id. at p. 1154, 11 Cal Rptr.2d 109.) After the trial court granted a defense motion for nonsuit, the plaintiffs appealed.
This court reversed and remanded. Noting that we had reached much the same conclusion in Mullen as the superior court had adopted in its general order 21 (Wheeler, supra, 8 Cal.App.4th 1152 at p. 1155,11 Cal.Rptr.2d 109), our opinion went on, however, to hold that plaintiffs nevertheless should be permitted to attempt to establish the theory underlying their claim for Sindell relief. That theory was that friction "brake pads were fungible to the extent that a pad of a given size, regardless of who made it, could be used on a variety of different vehicles .... that the pads manufactured by defendants were all composed solely of chrysotile asbestos fiber ... [and] the brake pads all contained between 40 and 60 percent asbestos by weight." (Id at p. 1156, 11 Cal.Rptr.2d 109.) Because the plaintiffs alleged that a "single type of asbestos fiber, chrysotile, was used in all the pads, and the amount of asbestos by weight in the pads varied within a limited range," the Wheeler opinion reasoned, "they are fungible for the purposes of Sindell by virtue of containing roughly comparable quantities of the single asbestos fiber, chrysotile." (Ibid.) It followed, our opinion concluded, that "the peculiar facts presented by exposure to asbestos fiber from brake pads" made general order 21 "inapplicable to the facts of the claim stated by plaintiffs." Plaintiffs, Wheeler went on to point out, "have not proven the elements of a market share case; we hold only that they should be allowed to attempt it."[2](Id at p. 1158, 11 Cal.Rptr.2d 109.)
*825 It is not difficult to appreciate the intellectual consistency between Mullen (holding that a market share theory of liability does not apply generally to asbestos litigation) and the exception carved out in Wheeler (holding that a Sindell theory of liability in asbestos litigation might be applicable under certain narrowly defined circumstances). The latter is simply a special subclass of asbestos cases held to be properly amenable to Sindell relief because of underlying factual analogies to the DES cases. It is, however, fair to ask how courts are to identify the line separating these two incommensurate paradigms. Some guidance regarding the application of Sindell principles in asbestos-related tort litigation is furnished by the high court's opinion in Rutherford v. Owens-Illinois, Inc. (1997) 16 Cal.4th 953, 67 Cal. Rptr.2d 16, 941 P.2d 1203 (Rutherford).
At issue before the Rutherford court was the validity of a local rule of the Solano County Superior Court purporting to "shift[ ] the burden of proof to defendants in asbestos cases tried on a products liability theory to prove that their products were not a legal cause of the plaintiffs injuries...." (Rutherford, supra, 16 Cal.4th 953 at p. 957, 67 Cal.Rptr.2d 16, 941 P.2d 1203), that is, a local court rule opposite to San Francisco's general order 21 at issue in Wheeler. (Id. at p. 957, 67 Cal.Rptr.2d 16, 941 P.2d 1203, italics in original.) In assessing the validity of the contested local rule, the California Supreme Court discussed at length the validity of a Summers-derived theory of tort liability and its burden-shifting approach in "asbestos-related latent personal injury actions brought against multiple suppliers of asbestos products." (Id. at p. 971, 67 Cal.Rptr.2d 16, 941 P.2d 1203.) The Rutherford court began its discussion by observing that "[t]he majority of courts have refused to extend the doctrine of alternative liability and its burden-shifting rule to asbestos-related latent personal injury actions brought against multiple suppliers of asbestos products. These cases have found the factors which support application of Summers alternative liability and burden shifting readily distinguishable from the facts typically involved in complex asbestos litigation." (Ibid.)
But the Supreme Court's Rutherford opinion does more than offer a series of observations concerning the judicial reception given Sindell in asbestos personal injury litigation in other American jurisdictions. It goes on to discuss, with evident approval, the reasons that prompted a great majority of reviewing courts across the nation to decline to apply burden-shifting market share principles in the context of asbestos exposure tort litigation. (Rutherford, supra, 16 Cal.4th 953 at pp. 971-975, 67 Cal.Rptr.2d 16, 941 P.2d 1203.) Many of the courts that had rejected Sindell's application to asbestos-related tort claimsfrom the Ohio Supreme Court (Goldman v. Johns-Manville Sales Corp. (1987) 33 Ohio St.3d 40, 514 N.E.2d 691) to the federal district court for the Western District of Pennsylvania (Vigiolto v. Johns-Manville Corp. (W.D.Pa.1986) 643 F.Supp. 1454)did so on the ground that not all potential tortfeasors were joined as defendants (Rutherford supra, 16 Cal.4th at p. 974, 67 Cal.Rptr.2d 16, 941 P.2d *826 1203).[3] The Rutherford court, however, divined a more fundamental reason for rejecting a burden-shifting approach to asbestos personal injury litigation"the limits on the plaintiffs burden of proof on causation...." (Ibid.) This followed, the Rutherford court reasoned, because a plaintiff's burden of proving causation in such circumstances does not include a requirement of establishing "the scientifically unknown details of carcinogenesis, or ... the unknowable path of a given asbestos fiber." (Id. at p. 976, 67 Cal. Rptr.2d 16, 941 P.2d 1203.)[4]
*827 In the briefing before this court, respondent and supporting amicus curiae contend our Wheeler decision is no longer good law, having been disapproved, at least implicitly, by Rutherford's analysis, if not by its precise holding. Given this line of development and the current state of the case law, we consider the question whether this court is now in a position to draw any firm conclusions about Wheeler's ongoing vitality. Only a modest one, we will conclude that the exception approved by this court in Wheeler has no application to the factual record made in this case. We also reach the complementary conclusion that because we are not required to, we do not here decide the contemporary validity of Wheeler in circumstances in which it might properly be applicable. We reach these conclusions for the following reasons.
Significantly for present purposes, the Rutherford opinion observes that "[o]nly in one circumstance have we relieved toxic tort plaintiffs of the burden of showing exposure to the defendant's product: where hundreds of producers had made the same drug from an identical formula, practically precluding patients from identifying the makers of the drugs they took. (Sindell, supra, 26 Cal.3d at pp. 610-613 [163 Cal.Rptr. 132, 607 P.2d 924].)" (Rutherford, supra, 16 Cal.4th at p. 976, 67 Cal.Rptr.2d 16, 941 P.2d 1203, italics added.) We think it is evident that supporting the application of Sindell's group liability principles by this court in Wheeler was the singular fact alleged by the plaintiffs therethe asserted chemical homogeneity of the asbestos fibers composing friction brake products. Writing for this court in Wheeler, Justice Poché expressly said as much: "On the issue of fungibility plaintiffs offered to prove that the brake pads were fungible to the extent that a pad of a given size, regardless of who made it, could be used on a variety of different vehicles. Furthermore, they note that the pads manufactured by defendants were all composed solely of chrysotile asbestos fiber. Finally, the brake pads all contained between 40 and 60 percent asbestos by weight." (Wheeler, supra, 8 Cal.App.4th 1152 at p. 1156, 11 Cal.Rptr.2d 109.)
Given this asserted compositional uniformity, the Wheeler plaintiffs' additional allegation that at the time of their exposure to friction asbestos dust "these worn brake pads could no longer be identified by brand"[5](Wheeler, supra, 8 Cal.App.4th 1152 at p. 1155, 11 Cal.Rptr.2d 109), was sufficient to bring the case within the liability principles approved by our Supreme Court in Sindell as the functional equivalent to the situation confronting the DES plaintiff. As the court explained, "[a] single type of asbestos fiber, chrysotile, was used in all the pads, and the amount of asbestos by weight in the pads varied within a limited range. While brake pads are not absolutely interchangeable each for one another and hence are not fungible from the standpoint of an auto mechanic, they are fungible for the purposes of Sindell by virtue of containing roughly comparable quantities of the single asbestos fiber, chrysotile." (Id. at p. 1156, 11 Cal.Rptr.2d 109.)
Here, the pleadings indicate Mr. Ferris was exposed not only to asbestos dust from friction brake products while working on his and his neighbors' automobiles over the years, but also while working in West Coast naval shipyards in the six years spanning 1939 to 1945, and possibly while employed at San Quentin State Prison from 1960 to 1970, and as a furniture upholsterer from 1950 to 1960. The plaintiffs in Wheeler occupied a comparable situation, *828 having been exposed to asbestos particles from both friction products and other, nonfriction sources. (Wheeler, supra, 8 Cal.App.4th at p. 1155, 11 Cal. Rptr.2d 109.) The Wheeler plaintiffs, however, limited their request for Sindell relief to those manufacturers of friction brake products, eschewing that remedy with respect to the defendant nonfriction manufacturers. (Ibid.)
At oral argument of this cause, plaintiffs' counsel contended a like limitation on his clients' Sindell claim was sought in the trial court and that, while Judge Tomar Mason had never passed specifically on the applicability of the Wheeler "fungibility" exception to Mullen, the defense in limine motion was argued by both sides on the assumption"as if'plaintiffs' Sindell claim satisfied the "fungibilty" prong.[6] While we are unable to confirm that supposition from the record before us, as we explain, we think the point is academic in view of other flaws in plaintiffs' proof on the Sindell issue. Chief among these was the acknowledgement by plaintiffs' expert witness, Dr. Ben-Zion, that he was unable to compute Gatke's share of the national friction products market during the relevant time period.
Both at oral argument and in briefing, plaintiffs' counsel referred to the requirement of proof of an individual manufacturer's national market share as the "phantom fifth prong" for Sindell relief, suggesting such proof is not, as a matter of law, a requisite for establishing market share liability. We disagree. Indeed, it is plain both from Justice Mosk's opinion for the majority in Sindell and from the logic of the theory underlying market share tort liability itself that such proof is an essential predicate to relief. This is so because the very uniqueness of the remedy crafted by the court in Sindella modification of the alternative liability theory adopted by the court in Summerswas justified by the Supreme Court as mitigating what otherwise would be a manifest injustice.
"If plaintiff joins ... the manufacturers of a substantial share of [the offending product], the injustice of shifting the burden of proof to defendants to demonstrate that they could not have made the substance which injured plaintiff is significantly diminished.... [¶] The presence in the action of a substantial share of the appropriate market also provides a ready means to apportion damages among the defendants. Each defendant mil be held liable for the proportion of the judgment represented by its share of that market unless it demonstrates that it could not have made the product which caused plaintiffs injuries .... [¶] Under this approach, each manufacturer's liability would approximate its responsibility for the injuries caused by its own products. Some minor discrepancy in the correlation between market share and liability is inevitable; therefore, a defendant may be held liable for a somewhat different percentage of the damage than its share of the appropriate market would justify.... But just as a jury cannot be expected to determine the precise relationship between fault and liability in applying the doctrine of comparative fault [citation] or partial indemnity [citation] the difficulty of apportioning damages among the defendant producers in exact relation to their market share does not seriously militate against the rule we adopt." (Sindell, supra, 26 Cal.3d at pp. 612-613, 163 Cal.Rptr. 132, 607 P.2d 924, italics added.)
In addition to this reasoning, the chief law review article on which the Sindell *829 court relied in explicating the market share theory (see Sindell, supra, 26 Cal.3d at pp. 597, 611, 163 Cal.Rptr. 132, 607 P.2d 924) also ties proportional tort liability to proof of an individual defendant's share of the market: Speaking of the DES cases, the comment in the Fordham Law Review reasoned that "Although joint liability may seem inequitable under these circumstances [i.e., mass tort cases presenting numerous defendants] it need not be. Since there is not an equal possibility of causation for each defendant, and the possibility of causation can best be estimated by market share, damages should be apportioned according to market share." (Comment, DES and a Proposed Theory of Enterprise Liability (1978) 46 Fordham L.Rev. 963, 994, italics added.)
Coupled to that circumstance is the fact that Mr. Ferris was able to identify two of the manufacturers to whose friction asbestos brake products he was exposed and conceded he had no evidence substantiating exposure to any asbestos products manufactured by defendant Gatke. In answers to interrogatories propounded by defendant Gatke, plaintiffs stated that during the course of doing brake repair work on his and his neighbors' automobiles "[d]ecedent recalled RAYBESTOS and BENDIX brakes." It is, of course, precisely the inability of the plaintiffs in both Summers and Sindell to identify the causal source of their injuries that was said by our Supreme Court to justify reversing the usual burden of proving causation, allocating to the defendant tortfeasors the burden of negating their role in causing the plaintiffs injury.
The final consideration that weighs on us is one of legal policy. From Sindell onward courts confronting this unique group liability issue have underlined repeatedly the extraordinary departure from conventional tort law doctrine, with its Aristotelian conception of causation, such notions represent. The Lineaweaver court's opinion gives voice to one source of these concerns when it observes that "it is the wrongdoer who caused the harm that should bear the cost, and it serves no justice to fashion rules which allow responsible parties to escape liability while demanding others ... compensate a loss they did not create." (Lineaweaver, supra, 31 Cal.App.4th at p. 1418, 37 Cal. Rptr.2d 902.) We think a principle cognate to that recognition is that courts should employ such group liability concepts with great caution and only after being satisfied that the circumstances invoked in support of their application are truly compelling. Those criteria, we conclude, are not and cannot be met by plaintiffs in this case.

2. It was not error to grant defense motions for nonsuit on plaintiffs' civil conspiracy claims.

As noted at the outset (ante, at p. 821), the trial court also granted defendant Gatke's motion for nonsuit on plaintiffs' claims for negligence and products liability, as well as their civil conspiracy claims based in negligence and products liability. It did so on the express ground plaintiffs had failed to establish a legal duty running from Gatke to Harley Ferris, there being "no offer that there's evidence that the decedent actually used the Gatke products." Plaintiffs attack that determination here as reversible error.
Deposition testimony by both of Mr. Ferris's sons, Jack and Gary, as well as Augusta's deposition testimony, established that none could recall him using friction brake products manufactured by Gatke. And in answers to interrogatories propounded by the defense, plaintiffs were unable to offer any testimony descriptive of the kinds of brake shoes Harley Ferris *830 actually used in working on his family's and neighbors' automobiles that might have tied Gatke's products to Ferris.
Despite the absence of evidence supporting a reasonable inference that Mr. Ferris was exposed to defendant's friction brake products, plaintiffs contend the trial court erred reversibly in rejecting their civil conspiracy-based causes of action for negligence, strict liability, fraud, and intentional concealment. In oral argument before the trial court on September 1, 2000, plaintiffs' counsel summarized the evidence they intended to rely on in support of their civil conspiracy claims. Gatke, he contended, was a friction brake pioneer "in the '30s, '40s and '50s," and "in the 1930s, they helped sponsor a specific study with other companies of the hazards of asbestos generally. They contributed, along with Raybestos Manhatt[a]n and Johns-Manville and others" to scientific experiments with animals, exposing them to asbestos and studying the effects at the Saranac Laboratory, a private research facility near Saranac Lake, New York. "And in addition ...," counsel continued, "they formed a group called the Asbestos Textile Institute or the ATI...." Among other things, plaintiffs argued, ATI controlled the publication rights to the research results of the Saranac Laboratory investigation "so that it [i.e., the Saranac research results] could be sanitized. In fact, it was sanitized" by removing all references to a link between asbestos exposure and cancer. "Our evidence" counsel told the trial court, "will prove that Gatke in concert with Raybestos Manhatt[a]n, Bendix and other members [of the Institute] committed the tort of negligence [in] manufacturing and sale of products that failed to perform as ... an ordinary consumer would expect...." These were examples, according to counsel's argument, "of tortious misconduct that Gatke will be shown to have done pursuant to the common design and in concert with others like Raybestos Manhatt[a]n and Johns-Manville."
As indicated, the trial court granted defendant's motion for nonsuit on plaintiffs' civil conspiracy claims. For reasons explored in greater detail in our opinion in a companion appealChavers v. Gatke Corp. (2003) 107 Cal.App.4th 606, 611-512, 132 Cal.Rptr.2d 198also filed March 28, 2003, we hold the trial court's nonsuit ruling is supported by an unwavering line of California Supreme Court precedent. Beginning with Gruenberg v. Aetna Ins. Co. (1973) 9 Cal.3d 566, 108 Cal. Rptr. 480, 510 P.2d 1032, reaffirmed in Doctors' Co. v. Superior Court (1989) 49 Cal.3d 39, 260 Cal.Rptr. 183, 775 P.2d 508, and culminating (for now) in Applied Equipment Corp. v. Litton Saudi Arabia, Ltd. (1994) 7 Cal.4th 503, 28 Cal.Rptr.2d 475, 869 P.2d 454, the California high court has held repeatedly that, as a matter of law, a civil conspiracy to commit tortious acts can be formed only by parties already under a legal duty to the plaintiff, the breach of which will support an action in tort against the members of the conspiracy individually. Put another way, where a plaintiff asserts the existence of a civil conspiracy among the defendants to commit tortious acts, the source of any substantive liability arises out of an independent duty running to the plaintiff and its breach; tort liability cannot arise vicariously out of participation in the conspiracy itself. (Chavers v. Gatke Corp., supra, 107 Cal.App.4th at p. 614, 132 Cal.Rptr.2d 198.) (See fn.7.) In light of these controlling principles, the trial court did not err in granting the motion for nonsuit.[7]


*831 I, CONCLUSION
The judgment of the superior court is affirmed.
We concur: KAY, P.J., and RIVERA, J.
NOTES
[1]  As others have noted, "`[describing the theory of market share liability is much easier than defining it: [If] "Under this doctrine, the traditional prerequisite of identifying the manufacturer of the injury-causing product is eliminated when the product is a generic item produced by several manufacturers. In such cases, plaintiffs need only allege inability to identify the actual manufacturer and join as defendants those manufacturers that compose a `substantial share' of the market.... Th[e] theory shifts the burden of proof to each manufacturer to prove its innocence ... [¶] If ... plaintiff successfully establishes liability, damages are simply apportioned among defendants on the basis of each defendant's share of the product market.... A defendant can avoid liability only by proving that it did not produce the specific product that harmed the plaintiff."'" (Mullen v. Armstrong World Industries, Inc. (1988) 200 Cal.App.3d 250, 255, fn. 6, 246 Cal.Rptr. 32, quoting Hannon v. Waterman S.S. Corp. (E.D.La.1983) 567 F.Supp. 90, 91, fn. 1.)
[2]  In Richie v. Bridgestone,'Firestone, Inc. (1994) 22 Cal.App.4th 335, 27 Cal.Rptr.2d 418, a panel of this Division gave Wheeler full retroactive effect, over a dissent by Presiding Justice Anderson, who attacked Wheeler itself as wrongly decided: "Between 1988 and 1992 nothing changed. Asbestos was still as generic as before, general order 21 was concededly as `sound' as when adopted, and no new appellate decision or commentary had appeared. Indeed, Wheeler is devoid of both (1) citation to any authority in support of its holding and (2) any good reason for rejecting Mullen as controlling." (Richie v. Bridgestone/Firestone, Inc., supra, 22 Cal.App.4th 335 at p. 343, 27 Cal.Rptr.2d 418.)
[3]  The high court's Rutherford opinion relies on a phalanx of judicial decisions from across the nation, overwhelmingly declining to apply a Summers/Sindell-based burden-shifting instruction to asbestos-related personal injury tort litigation. (Rutherford, supra, at pp. 971-973, 67 Cal.Rptr.2d 16, 941 P.2d 1203; see, e.g., Black v. Abex Corp. (N.D.1999) 603 N.W.2d 182, 185; White v. Celotex Corp. (9th Cir.1990) 907 F.2d 104, 106; Robertson v. Allied Signal, Inc. (3d Cir.1990) 914 F.2d 360, 380; Leng v. Celotex Corp. (Ill.1990) 196 Ill. App.3d 647, 143 Ill.Dec. 533, 554 N.E.2d 468, 470-471; Gaulding v. Celotex Corp. (Tex. 1989) 772 S.W.2d 66, 70-71; Sholtis v. American Cyanamid Co. (App.Div.1989) 238 N.J.Super. 8, 568 A.2d 1196, 1203-1205; Case v. Fibreboard Corp. (Okla.1987) 743 P.2d 1062, 1064; In re Asbestos Litigation (Del.Super.Ct. 1986) 509 A.2d 1116, 1118; Blackston v. Shook & Fletcher Insulation Co. (11th Cir.1985) 764 F.2d 1480, 1483; Celotex Corp. v. Copeland, supra, 471 So.2d 533, at pp. 537-539; In re Related Asbestos Cases (N.D.Cal.1982) 543 F.Supp. 1152; cf. In the Matter of New York State Silicone Breast Implant Litigation (1995) 166 Misc.2d 85, 631 N.Y.S.2d 491; see also Prosser & Keeton on Torts (5th ed.1984) § 103, at p. 714; but cf. Menne v. Celotex Corp. (10th Cir.1988) 861 F.2d 1453, 1467.)
[4]  Two First District decisions, one filed before Rutherford and the other after, reach conclusions consistent with Rutherford. In Lineaweaver v. Plant Insulation Co. (1995) 31 Cal. App.4th 1409, 37 Cal.Rptr.2d 902 (Lineaweaver), a. decision predating Rutherford, Division One of this court had before it a negligence case brought by three plaintiffs. In a bifurcated trial against a lone defendantPlant Insulation Companythe jury returned liability and damages verdicts for plaintiffs. The trial court granted nonsuit on the ground plaintiffs had failed to establish exposure to defendant's product, and appeals were taken. (Id. at p. 1413, 37 Cal.Rptr.2d 902.) The Lineaweaver court affirmed, rejecting a Sindell/Summers-derived theory of group liability in the asbestos context. "Asbestos products have widely divergent toxicities," the court wrote. "Unlike the negligent hunters of Summers, all asbestos suppliers did not fire the same shot. Yet, under a burden-shifting rule, all suppliers would be treated as if they subjected plaintiff to a hazard identical to that posed by other asbestos products." (Id. at p. 1418, 37 Cal.Rptr.2d 902.) And in a recent, post-Rutherford decision by a panel of this DivisionMcGonnell v. Kaiser Gypsum Co. (2002) 98 Cal.App.4th 1098, 120 Cal.Rptr.2d 23 (McGonnell)we succinctly acknowledged the changes wrought by Rutherford. At issue in McGonnell was the soundness of the trial court's order granting the defense summary judgment on the ground plaintiffs had failed to prove exposure to defendant's products. (Id. at p. 1102, 120 Cal.Rptr.2d 23.) Affirming, we said this: "A threshold issue in asbestos litigation is exposure to the defendant's product. The plaintiff bears the burden of proof on this issue. (Rutherford, supra, 16 Cal.4th 953 at pp. 975-976 [67 Cal.Rptr.2d 16, 941 P.2d 1203]; Lineaweaver v. Plant Insulation Co., supra, 31 Cal.App.4th 1409, 1415-1416 [37 Cal.Rptr.2d 902].) If there has been no exposure, there is no causation." (Dumin v. Owens-Corning Fiberglas Corp. (1994) 28 Cal.App.4th 650, 655, 33 Cal. Rptr.2d 702). Plaintiffs may prove causation in an asbestos case by demonstrating that the plaintiff's ... exposure to the defendant's asbestos-containing product in reasonable medical probability was a substantial factor in contributing to the aggregate dose of asbestos the plaintiff ... inhaled or ingested, and hence to the risk of developing asbestos-related cancer. (Rutherford, supra, at pp. 976-977, 67 Cal.Rptr.2d 16, 941 P.2d 1203.)" (McGonnell, supra, 98 Cal.App.4th 1098 at p. 1103, 120 Cal.Rptr.2d 23.) In neither of these cases, nor in Rutherford, however, did we or the Supreme Court deal with asbestos exposure in the friction products context or discuss the Wheeler exception.
[5]  This circumstance was the result, we gather, of the disappearance of the manufacturers' branding as the friction brake linings were worn away through use.
[6]  Indeed, defense counsel appears to have agreed the trial court reached its ruling on the assumption the Wheeler criteria for Sindell reliefincluding fungibilitywere satisfied.
[7]  Plaintiffs also contend the trial court erred by granting a defense motion for nonsuit without first affording their counsel an opportunity to make an opening statement. It is true the nonsuit statuteCode of Civil Procedure section 581ccontemplates a ruling on a motion for nonsuit "[o]nly after, and not before, the plaintiff has completed his ... opening statement." (Code Civ. Proc, § 581c, subd. (a).) Here, however, if the trial court erred, it did so only at the invitation of plaintiffs' counsel. In preliminary proceedings on August 31, 2000, the trial judge and plaintiffs' and defendant's counsel discussed in open court the procedure to be followed in disposing of a defense in limine motion to exclude evidence supporting Sindell relief at the upcoming jury trial. As the discussion turned to the issue of the alleged conspiracy between defendant Gatke and other asbestos manufacturers, defense counsel suggested "the proper procedure is that [plaintiffs] make their offer of proof and that they stipulate that the nonsuit motion is made on that offer of proof." "All right," Judge Mason replied. "Then I believe all of those issues will be taken up properly tomorrow at 9:30. Is that agreeable?" While defense counsel indicated agreement with that statement, there was no response from plaintiffs' attorneys. On the following day, proceedings resumed. Although defendant contends counsel stipulated to this variant on the procedure prescribed by Code of Civil Procedure section 581c, subdivision (a), plaintiffs deny they stipulated. The record bears them out; there is no indication in the transcript that plaintiffs' counsel ever agreed expressly to substitute an offer of proof for the opening statement. Rather, plaintiffs' counsel was silent until after the trial court, evidently proceeding on the assumption the parties had stipulated, had ruled by granting the motion for nonsuit. Or, as Judge Mason stated to plaintiffs' counsel in response to his procedural objection to her ruling, "You put me in a difficult position stating this particular objection now, since: Had this objection been stated before the court's ruling at the last hearing, I might have been able to accommodate your apparent request to have the ruling reserved until after opening statements.... And I assume that actually counsel preferred to know the Court's rulings so that no further time would be invested in the case if the Court found the Plaintiffs' offers insufficient." Assuming it was error to rule on the motion for nonsuit following an offer of proof rather than an opening statement, it was error invited by counsel's silent failure to timely bring any objection to the trial judge's attention before she had ruled. (Cf. Weber, Lipshie & Co. v. Christian (1997) 52 Cal.App.4th 645, 658, 60 Cal.Rptr.2d 677 [plaintiff estopped to urge error in choice of law on appeal where it consciously pursued contrary course in trial court]; see also Giest v. Sequoia Ventures, Inc. (2000) 83 Cal.App.4th 300, 302-303, 99 Cal. Rptr.2d 476 [use of stipulated offer of proof in lieu of opening statement]; 9 Witkin, California Procedure, Appeal, §§ 383-385, pp. 434-436.)
