Yesterday, the Texas Supreme Court reaffirmed the substantial-factor standard of causation recognized in Borg-Warner Corp. v. Flores, and held that it applies in mesothelioma cases. The Court made clear that in multiple-exposure cases, the plaintiff must establish the dose of asbestos fibers to which he was exposed by his exposure to the defendant’s product. The plaintiff cannot prove substantial factor causation without scientifically reliable expert testimony that the plaintiff’s exposure to the defendant’s product more than doubled the plaintiff’s risk of contracting the disease.
Timothy Bostic’s family sued Georgia-Pacific Corp. and other asbestos-related product manufacturers claiming that his fatal mesothelioma was caused by exposure to their products. Georgia-Pacific was the sole remaining defendant at trial, where the Bostics alleged negligence, gross negligence, and strict product liability for a marketing defect.
The jury awarded the Bostics $7.55 million in compensatory damages and $6 million in punitive damages and found Georgia-Pacific 75% responsible. But the trial court granted Georgia-Pacific’s post-trial motion for mistrial based on juror, bailiff, and judge misconduct. More than a year later, the Bostics filed a motion to vacate the order and enter judgment. At that time, the trial court entered an amended final judgment against Georgia-Pacific for more than $12 million in actual and punitive damages. Georgia-Pacific appealed.
The Dallas Court of Appeals reversed the trial court and rendered judgment for Georgia-Pacific, finding that there was legally insufficient evidence of specific causation. Georgia-Pacific Corp. v. Bostic, 320 S.W.3d 588 (Tex. App.—Dallas, 2010). The court held that the Bostics failed to prove that Bostic’s exposure to Georgia-Pacific’s asbestos was a substantial factor in bringing about his injury, noting that even the Bostics’ expert could not conclude that Bostic would not have developed mesothelioma absent exposure to Georgia-Pacific’s product.
The Texas Supreme Court affirmed the court of appeals, holding that in all asbestos cases involving multiple sources of exposure, including mesothelioma cases, the standard of substantial factor causation recognized in Borg-Warner applies. To meet this standard, the plaintiff must present defendant-specific evidence of the approximate dose to which the plaintiff was exposed and evidence that the dose was a substantial factor in causing the disease.
The Court expressly rejected the Bostics’ “each and every exposure” theory, under which each asbestos exposure (at least to the point of the first cancer cell’s development) causes or potentially causes the disease. The Court reasoned that such an approach negates the plaintiff’s burden to prove causation by a preponderance of the evidence. The Court further held that plaintiffs in multiple-exposure cases are not required to prove that but for the plaintiff’s exposure to the defendant’s product, the plaintiff would not have contracted the disease. Given the nature of the disease process in a multiple-exposure case, the Court reasoned that it may be impossible to show that the plaintiff would not have become ill but for the exposure to a particular defendant’s product, even if exposure from the defendant was by itself sufficient to cause the disease.
The Court also reasoned that in a multiple-exposure case, mere proof of any exposure to a defendant’s product is legally insufficient to prove specific causation. Instead, the plaintiff must establish the dose of asbestos fibers to which he was exposed by his exposure to the defendant’s product. The dose must be quantified, but need not be established with mathematical precision. In proving that the defendant’s product was a substantial factor in causing the plaintiff’s disease, the Court held that the plaintiff must prove with scientifically reliable expert testimony that the plaintiff’s exposure to the defendant’s product more than doubled the plaintiff’s risk of contracting the disease. The defendant’s product is not a substantial factor in causing the plaintiff’s disease if, in light of the evidence of the plaintiff’s total exposure to other toxins, reasonable persons would not regard the defendant’s product as a cause of the disease.
In applying these principles, the Court affirmed the judgment of the court of appeals that the Bostics failed to present legally sufficient evidence of causation. The Bostics could not rely on their experts’ testimony that each and every exposure to asbestos should be considered a cause of Bostic’s disease. And without evidence quantifying either the overall dose, and/or the dose specific to Georgia-Pacific to which Bostic was exposed, the Bostics could not prove that exposure to Georgia-Pacific’s product more than doubled Bostic’s chances of contracting mesothelioma. Without this proof, the Bostics failed to prove that Georgia-Pacific’s product was a substantial factor in causing Bostic’s disease.