The Pennsylvania Supreme Court last week issued a potentially highly significant decision in the long-standing asbestos mass tort. See Betz v. Pneumo Abex LLC et al., No. J-87-2011 (Pa. May 23, 2012).
The issue is causation. Readers know that a tort plaintiff has to establish cause in fact and proximate cause. Cause in fact can mean "but for" the defendant's conduct, the plaintiff would not have been injured, or, in some cases, that the conduct was a "substantial factor" in causing the harm. In toxic tort cases, cause in fact includes general causation (the product can cause this type of disease) and specific causation (the product did cause this plaintiff's disease). Often, epidemiological proof is used to establish causation in a toxic tort context, but there are strengths and limitations to that type of evidence, which can show an association between the product and the disease, and which typically demonstrates that there is some specific relationship between the amount of exposure to the product and the amount of disease seen in the exposed population (a dose-response relationship). What may be unknown from the epidemiology (and other relevant scientific evidence) is whether there is a threshold of exposure below which there is no risk of disease, or whether any level of exposure carries a measurable increased risk of disease. Plaintiffs' experts often assume there is no safe level of exposure, and regulatory agencies may assume the same as a matter of public health policy; these latter assumptions do not establish legal causation given their cautionary, prophylactic nature. But what proof a plaintiff has that an extremely low level of exposure to a given defendant's product can or did cause his disease is a crucial issue in many toxic tort contexts.
In asbestos, the grandfather of all mass torts, plaintiffs' experts often seek to testify that "one fiber can kill," meaning there is no safe level of exposure to asbestos, and from that to conclude that that any exposure to any amount of asbestos from any defendant was a substantial factor contributing to the asbestos disease the plaintiff has. They say this even as they admit, as the epidemiology shows, that at all the measurable levels of exposure (no one can find a plaintiff exposed to just one fiber) asbestos-related disease demonstrates a clear dose-response relationship.
Back in 2005, plaintiff Simikian commenced a product liability action against several defendants, asserting causes of action grounded on multiple theories including strict liability. Mr. Simikian
alleged that, throughout a forty-four year career as an automotive mechanic, his exposure to asbestos-containing friction products, such as brake linings, caused his mesothelioma. Plaintiff indicated he would rely on expert opinion that each and every exposure to asbestos -- no
matter how small -- contributed substantially to the development of his asbestos-related
diseases: the the “any-exposure,” “any-breath,” or “any fiber” theory of legal (or substantial-factor) causation. See generally Summers v. Certainteed Corp., 606 Pa. 294, 316, 997 A.2d 1152, 1164-65 (2010) (discussing the requirement for a plaintiff to prove that a defendant’s product was a substantial factor in causing injury). Seeking to preclude such opinion testimony, defendants filed a motion under the Frye test (PA is a general acceptance jurisdiction), arguing that it barred this "novel" scientific evidence from the courtroom until it has achieved general acceptance in the relevant scientific community.
Plaintiffs relied on a Dr. Maddox, who provided for his opinion as to specific and proximate
causation that asbestos-related mesothelioma, like other diseases induced by toxic exposures, is a dose-response disease; that each inhalation of asbestos-containing dust from the use of
products has been shown to contribute to cause asbestos-related diseases, including mesothelioma. Each of the exposures to asbestos allegedly contributes to the total dose that causes mesothelioma and, in so doing, shortens the period necessary for the mesothelioma to develop. Plaintiff further argued that each exposure to asbestos is therefore a substantial contributing factor in the development of the disease that actually occurs; a court need not look at individual exposures or the identity of the product or the manufacturer. "As a matter of law, you just say, hey, you breathed asbestos from a product, oh, you are going to the jury."
The trial court requested expert reports, and then held an evidentiary hearing. The Common Pleas court centered its focus on the use of extrapolation, from high doses down to a single finer, which it found to be a linchpin of Dr. Maddox’s methodology and opinion supporting a finding of proximate cause. The court expressed concern with an “analytical gap” between the scientific proofs and the expert's conclusion. At the hearing, the expert admitted he did not consider epidemiology appropriate to consult regarding low-dose exposures, offering an "analogy" that has been used in the example of a glass of water. One drops marbles into the glass of water until the water finally overflows from the glass; is it the first marble or the last marble that causes the glass
to overflow? Well, both, or all of them, said the plaintiff expert.
The expert testified, however, that individual exposures differ in the potency of the fiber to
which an individual is exposed, to the concentration or intensity of the fibers to which one is exposed, and to the duration of the exposure to that particular material. Dr. Maddox agreed that scientists presently do not know the mechanism by which asbestos causes mesothelioma. Additionally, he recognized that his opinions were not based on any sort of direct attribution, but rather, were grounded entirely upon an assessment of increased risk.
The trial court sustained the Frye challenge and precluded the plaintiffs from adducing the any-exposure opinion. Overall, Judge Colville could find no credible explanation for how it was that Dr.
Maddox was able to determine if it was exposure to a particular defendant’s friction product that
caused a plaintiff’s mesothelioma, and not some other exposure to asbestos material. Even if one accepts that a single fiber may possibly increase the risk of developing disease, it did not accept that an unquantified (and potentially infinitesimal) increase in risk could serve as proof that a defendant’s product was a substantial cause of a plaintiff’s or decedent’s disease. Generally accepted scientific methodology may well establish that certain “high dose” asbestos exposure causes, or contributes to, a specific hypothetical plaintiff’s disease, but the plaintiffs had not proffered any generally accepted methodology to support the contention that a single exposure or an otherwise vanishingly small exposure has, in fact, in any case, ever caused or contributed to any specific individual’s disease, or even less so, that in this case such a small exposure did, in fact, contribute to this specific plaintiff’s disease.
Plaintiff appealed, and the Superior Court reversed, basically disagreeing with every aspect of the trial court's analysis. It relied on Ferebee v. Chevron Chemical Co., 736 F.2d 1529 (D.C. Cir. 1984), essentially for the proposition that, so long as an expert is willing to testify to an extrapolation, courts should permit its admission. (The notion that courts have no screening function is at odds with the last couple decades of federal court evidence law, just as it was at odds with most federal circuits at the time the DC CIrcuit opinion was written, and with states that have adopted Daubert and also those that still adhere to Frye.) Defendants then appealed.
Appellants (and their amici) offered extensive critiques of Dr. Maddox’s methodology from both scientific and logical perspectives, with the bottom line that the any-exposure opinion remains a hypothesis or assumption, and stressing Dr. Maddox’s inability to identify any peer-reviewed scientific support undergirding the opinion. While plaintiffs offered much argument on the effects of high doses of asbestos, they did not squarely address appellants’ arguments concerning differences in potency among asbestos fibers, or the potential that exposure to asbestos from a defendant’s product might be minimal in comparison to others.
The state Supreme Court noted that this case was selected among test cases for the any-exposure opinion as a means, in and of itself, to establish substantial-factor causation. The plaintiff's efforts to invoke case reports, animal studies, and regulatory standards to support the theory were ineffectual in terms of substantial-factor causation, since the most these can do is suggest that there is underlying risk from the defendants’ products, a proposition with which the trial court did not disagree. What was more of concern was the assessment of substantiality.
In this regard, Dr. Maddox’s any-exposure opinion was in irreconcilable conflict with itself. Simply put, one cannot simultaneously maintain that a single fiber among millions is substantially causative, while also conceding that a disease is dose-responsive. The any-exposure opinion, as
applied to substantial-factor causation, did not consider the three factors which Dr. Maddox himself explained needed to be considered in trying to estimate the relative effects of different exposures: potency, intensity, duration.
The court took on directly the analogy offered by Dr. Maddox in support of his position: the marbles-in-a-glass illustration changes materially upon the recognition that to be a fair comparison one must include the factors that the marbles are all non-uniform in size and shape, and microscopic so that millions are needed to fill the glass. From this frame of reference, it is very difficult to say that a single one of the smallest of microscopic marbles is a substantial factor in causing a glass of water to overflow.
Superior Court reversed; trial court affirmed.