The Texas Supreme Court ruled that a defendant will not have to pay a $12 million verdict in an asbestos case because there was inadequate proof the company’s products actually caused the alleged injury. See Bostic, et al. v. Georgia-Pacific Corp., No. 10-0775 (Texas 7/11/14).

In Borg-Warner Corp. v. Flores, 232 S.W.3d 765 (Tex. 2007), the court had discussed the standards imposed by Texas law for establishing causation in asbestos-disease cases. Flores had concerned a plaintiff suffering from asbestosis. This case involved mesothelioma, and the court held that the standard of substantial factor causation recognized in Flores also applied to mesothelioma cases.  The court did not impose a strict but-for causation standard, but held that the plaintiffs had failed to offer legally sufficient evidence of causation, and accordingly it affirmed the lower court's judgment.

Under section 431 of the Restatement Second of Torts, the Texas court had held that to establish causation in fact the plaintiff must prove that the defendant’s product was a substantial factor in causing the disease, and that mere proof that the plaintiff was exposed to “some” respirable fibers traceable to the defendant was insufficient. The word substantial is used to denote the fact that the defendant’s conduct has such an effect in producing the harm as to lead reasonable persons to regard it as a cause, using that word in the sense of responsibility.  Proof of mere frequency, regularity, and proximity of potential exposure to asbestos (sufficient in some states) is in Texas necessary but not sufficient, as it provides none of the quantitative information necessary to support causation under Texas law.  While the plaintiff was not required to establish causation with “mathematical precision,” the court clearly required defendant-specific evidence relating to the approximate dose to which the plaintiff was exposed, coupled with evidence that the dose was a substantial factor in causing the asbestos-related disease.

In rejecting a standard that “some” exposure would suffice, the court recognized that most chemically induced adverse health effects clearly demonstrate thresholds; so, there must be reasonable evidence that the exposure was of sufficient magnitude to exceed the threshold before a likelihood of causation can be inferred. Plaintiffs urged that the standards established in Flores were not applicable in a mesothelioma case because relatively smaller quantities of asbestos can result in mesothelioma.  The court concluded that the Flores framework for reviewing the legal sufficiency of causation evidence lent itself to both types of cases. Even in mesothelioma cases proof of “some exposure” or “any exposure” alone will not suffice to establish causation. While the experts in this case testified that smaller amounts of asbestos exposure can result in mesothelioma, that fact alone does not merit a different analysis. With both asbestosis and  mesothelioma, the likelihood of contracting the disease increases with the dose.  The court noted that If any exposure at all were sufficient to cause mesothelioma, everyone would suffer from it or at least be at serious risk of contracting the disease. Everyone is exposed to asbestos in the ambient air; it is plentiful in the environment, especially if you’re a typical urban dweller.  Plaintiff's expert confirmed that we all have some asbestos in our lungs, but that background levels are sufficiently low that they do not cause disease; instead, multiples of fibers many times over were required to cause mesothelioma.

More fundamentally, if the court were to adopt a less demanding standard for mesothelioma cases and accept that any exposure to asbestos is sufficient to establish liability, the result essentially would be not just strict liability but absolute liability against any company whose asbestos-containing product crossed paths with the plaintiff throughout his entire lifetime. However, exposure does not always result in disease. The court said it had never embraced the concept of industry-wide liability on grounds that proof of causation might be difficult. 

If an “any exposure” theory of liability was accepted for mesothelioma cases because science has so far been unable to establish the precise dose below which the risk of disease disappears, the same theory would arguably apply to all carcinogens. The any exposure theory effectively accepts that a failure of science to determine the maximum safe dose of a toxin necessarily means that every exposure, regardless of amount, is a substantial factor in causing the plaintiff’s illness. This approach negates the plaintiff’s burden to prove causation by a preponderance of the evidence.

Further, said the court, there are cases where a plaintiff’s exposure to asbestos can be tied to a defendant, but that exposure is minuscule as compared to the exposure resulting from other sources. Proof of any exposure at all from a defendant should not end the inquiry and result in automatic liability. The Restatement Third of Torts provides that when an actor’s negligent conduct constitutes only a trivial contribution to a causal set that is a factual cause of harm, the harm is not within the scope of the actor’s liability. The any exposure theory is also illogical in mesothelioma cases, where a small exposure can result in disease, because it posits that any exposure from a defendant above background levels could impose liability, while the background level of asbestos should be ignored. But the expert testimony in this case was undisputed that the background level varies considerably from location to location. The court could not see how the theory can, as a matter of logic, exclude higher than normal background levels as the cause of the plaintiff’s disease, but accept that any exposure from an individual defendant, no matter how small, should be accepted as a cause in fact of the disease. Under plaintiffs'  any exposure theory a background dose of 20 does not cause cancer, but a defendant’s dose of 2 plus a background dose of 5 somehow does.

Expanding on the notion of substantial factor, the court noted that in the Havner decision it had enunciated principles in toxic tort cases that (1) expert testimony of causation must be scientifically reliable, (2) the plaintiff must establish the elements of his claim by a preponderance of the evidence, and (3) where direct evidence of causation is lacking, scientifically reliable evidence in the form of epidemiological studies showing that the defendant’s product more than doubled the plaintiff’s risk of injury appropriately corresponds to the legal standard of proof by a preponderance of the evidence. These principles, said the court, should apply to asbestos cases. As to the availability of scientific studies, asbestos-related disease has been researched for many decades and the population of potentially affected persons numbers in the millions. A more than doubling of the risk must be shown through reliable expert testimony that is based on epidemiological studies or similarly reliable scientific testimony. 

Multiple-exposure cases raise the issues of how the finder of fact should consider exposure from sources other than the defendant, what proof might be required as to those other sources, and who has the burden of proof regarding those other sources. These are difficult questions, said the court, but a plaintiff should be required to establish more than a doubling of the risk attributable to the defendant’s product;  the court did not require a plaintiff to track down every possible source of asbestos exposure and disprove that those other exposures caused the disease. In multiple-exposure cases few if any plaintiffs could ever establish which particular fibers from which particular defendant caused the disease.  However, when evidence is introduced of exposure from other defendants or other sources, mere proof of more than a doubling of the risk may not suffice to establish substantial factor causation. Suppose, hypothesized the court, a plaintiff shows that his exposure to a particular defendant’s product more than doubled his chances of contracting a disease, but the evidence at trial also established that another source of the substance increased the chances by a factor of 10,000. In this circumstance, a trier of fact or a court reviewing the sufficiency of the evidence should be allowed to conclude that the defendant’s product was not a substantial factor in causing the disease.