It is virtually a law of legal physics in California that liability tends to expand until a critical mass of appellate courts rule that it has reached its limit, or the Supreme Court puts up a stop sign (a vanishingly rare occurrence).
This judicial tendency reaches its zenith in asbestos litigation. Asbestos cases feature a combination of factors that pressure-test the boundaries of traditional tort law. Asbestos fibers, in most cases, are relatively fungible, and the exposures are anecdotal and undifferentiated. The injuries have extremely long latency periods, leaving exposure details fuzzy, ancient lore. The biological mechanisms are largely mysterious. In many cases, the plaintiff can prove an asbestos injury but cannot reliably prove causation under traditional tort standards.
Traditional tort standards generally require a plaintiff to prove that the defendant’s product or conduct was a “substantial factor” in bringing about the injury. It has not been enough that the conduct or product merely increased the potential risk of injury. How then are plaintiffs in asbestos cases to show causation?
The California Supreme Court confronted this causation dilemma in Rutherford v. Owens-Illinois, Inc., 16 Cal.4th 953 (1997), a multi-defendant asbestos lung cancer case. The trial court’s remedy was to shift the burden to defendants to disprove causation once the plaintiff established his cancer was caused by some asbestos and he had been exposed to some asbestos from the defendant’s products. After a lengthy discussion of the causation problems, the Supreme Court rejected this drastic deviation from tort principles. Instead, the Court adopted a middle-ground solution – the burden stays with the plaintiff. However, instead of proving that the defendant’s product caused the asbestos-related injury, the plaintiff needed to prove only that the product was a substantial factor contributing to his risk of developing cancer. Plaintiff could succeed by showing the product added to his cumulative aggregate dose of asbestos, substantially increasing his cancer risk.
The Rutherford Court justified this departure from common law by citing the unique exigencies of asbestos litigation. Some courts and commentators have rationalized bending tort law rules for asbestos cases, and distinguishing other tort cases, by invoking the Latin phrase connoting uniqueness and limitation – “sui generis.” E.g., Nelson v. Matrixx Initiatives, Inc.,2012 WL 3627399, at *12-13 (N.D. Cal. Aug. 21, 2012), aff’d 592 F.App’x 591 (9th Cir. 2015); Cole v. Celotex Corp., 599 So. 2d 1058, 1065-66 (La. 1992); Aaron D. Twerski, An Essay on the Quieting of Products Liability Law, 105 Cornell L. Rev. 1211, 1229 & n.73 (2020) (“It does not require extensive citation to make the point that asbestos is not just another products liability case. Courts have held manufacturers of asbestos to a standard that is sui generis.”). But see Nemeth v. Brenntag N. Am., 2022 WL 1217464, at *3-5 (N.Y. Ct. App. Apr. 26, 2022) (holding that toxic tort causation standards apply to asbestos cases).
Accordingly, one would be right to assume until shown otherwise that Rutherford’s modification of plaintiffs’ causation burden was strictly limited to asbestos cases. And no published opinion since Rutherford has held that the “substantial contribution to the aggregate dose/risk” standard applies beyond asbestos cases. But toxic tort plaintiffs regularly seek to expand Rutherford’s risk contribution standard to other toxic torts. And they have succeeded in some trial courts, based on a superficial misreading of Bockrath v. Aldrich Chemical Co., 21 Cal.4th 71, 79-80 (1999).
Bockrath’s vague non-asbestos toxic tort complaint named over 50 defendants and a variety of products. The Supreme Court detailed the pleading requirements for toxic tort suits, including the allegation “that each defendant’s product was a substantial factor, as that term is defined in Rutherford,” in causing injury.
Plaintiffs (and some trial courts) have seized on this vague language to argue that Bockrath adopted Rutherford’s risk contribution causation standard for other types of toxic torts. But that argument does not withstand scrutiny.
As a pleadings case, Bockrath evaluated only what needed to be alleged in a multi-defendant toxic tort case. It did not discuss what is needed to prove causation or how to instruct a jury, a distinction the Court recognized in observing that Rutherford “addressed the question of proof of causation in the context of products liability actions ….”.
Moreover, Bockrath never discussed whether it should import Rutherford’s asbestos-specific risk contribution causation standard. Modern California tort law applies the “substantial factor” causation standard ubiquitously. Rutherford reaffirmed that standard and explained it before tweaking it to accommodate the sui generis circumstances presented by asbestos litigation.
Bockrath discussed Rutherford at length, but never mentioned the risk contribution standard. Indeed, Bockrath quoted only Rutherford’s explanation of the basic substantial factor test and requirement of expert testimony “that the defendant’s conduct contributed to [the] plaintiff’s injury.” Accordingly, the argument for an extension requires acceptance of the notion that by merely mentioning that the “substantial factor” standard “as defined in Rutherford” is part of the plaintiff’s pleading burden, the Court intended to drastically modify the causation requirements in toxic tort cases generally.
That strains credulity. When Bockrath held plaintiffs must allege substantial factor causation as defined in Rutherford, it merely required that plaintiffs allege the product was a “substantial factor in bringing about the injury.” (emphasis added). All the key elements of Rutherford’s risk contribution standard are nowhere to be found in the Bockrath opinion; the words “aggregate,” “dose,” and “risk” are entirely absent.
If the Court intended to expand the exception, it would presumably explain that it was doing so and guide lower courts by explaining the new boundaries. And it would presumably require that the standard make sense in other contexts. But in multi-defendant occupational exposure cases like Bockrath, the products are usually diverse, not fungible or even comparable. They typically have different formulas, constituents, toxicological properties, risks, no-adverse effect levels, applications, and biological mechanisms. Such cases, therefore, lack a singular “aggregate dose” of any one toxin and thus have no rational basis for allowing liability to be based on contribution to a common, unitary risk.
Under these circumstances, there is no reason to believe Bockrath meant to expand Rutherford’s risk contribution causation standard to non-asbestos cases virtually sub silentio. Supreme courts shaping the common law do not operate that way. Rutherford addressed a unique problem with a unique solution. Sui generis. It was never meant to radically alter the landscape of tort law generally.
And yet, the risk contribution standard continues to be advanced and applied in non-asbestos toxic tort cases.
To abate this mission creep, the courts must dig below the surface and rigorously examine exactly what the Supreme Court meant to do in Bockrath. To date, unfortunately, they have shown little inclination to do so.