The history of asbestos litigation in the United States has been rife with a frequent reliance by plaintiffs on “junk science” in medical expert testimony, often involving various theories of causation.  Gradually courts have rejected these theories, including the “single fiber,” “every breath,” or “every exposure,” theory, and debunked them as illogical and unscientific.  More than a dozen courts in multiple jurisdictions have excluded or criticized the “every breath” theory and issued rulings making it more difficult for plaintiffs to rely on such testimony. 

On September 26, 2013, the Pennsylvania Supreme Court issued just such a decision when it rejected the “every breath” theory and articulated several governing principles on the admissibility of expert testimony.  The decision reinstated an order of the trial court granting a motion for summary judgment by the defendants in the litigation, holding that plaintiffs could not prove causation based on expert testimony that relied on an “every exposure theory.”  Howard et al. v. A.W. Chesterton Co. et al., Nos. 48 EAP 2012, 49 EAP 2012, 50 EAP 2012, 2013 WL 5379379, at *3 (Pa. Sept. 26, 2013).  This decision strengthens already strong Pennsylvania precedent on this issue and will make it challenging for plaintiffs to defeat summary judgment motions brought by de minimis exposure defendants.

A fundamental issue in asbestos litigation is the amount of evidence required to prove that “exposure” to an asbestos-containing product was a substantial contributing factor in a plaintiff’s disease.  The “every breath” theory claims that each and every exposure, no matter how small, even if it is a single breath of a single asbestos fiber, is sufficient to establish causation for asbestos-related diseases.  In 2012, the Pennsylvania Supreme Court rejected the notion that “each and every fiber” of asbestos amounted to a substantial cause of disease and held that such expert testimony was properly excluded at trial.  Betz v. Pneumo-Abex, LLC, et al., 615 Pa. 504, 44 A.3d 27 (Pa. 2012).  The Betz opinion is consistent with case-specific holdings in other prior Pennsylvania precedent, including Summers v. CertainTeed Corp., 606 Pa. 294, 997 A.2d 1152 (2010); Gregg v. V-J Auto Parts Co., 596 Pa. 274, 943 A.2d 216 (2007); and In re: Asbestos Litigation, No. 0001, 2008 Phila. Ct. Com. Pl. LEXIS 229 (C. P. Philadelphia, Sept. 24, 2008).

In Howard, the Court clarified the admissibility of related testimony that appears frequently in asbestos litigation, holding that:

  • [I]n cases involving dose-responsive diseases, expert witnesses may not ignore or refuse to consider dose as a factor in their opinions.
  • Bare proof of some de minimus exposure to a defendant’s product is insufficient to establish substantial-factor causation for dose-responsive diseases.
  • Relative to the testimony of an expert witness addressing substantial-factor  causation in a dose-responsive disease case, some reasoned, individualized  assessment of a plaintiff’s or decedent’s exposure history is necessary.
  • Summary judgment is an available vehicle to address cases in which only bare de minimus exposure can be demonstrated and where the basis for the expert’s testimony concerning substantial-factor causation is the any-exposure theory.

Howard, 2013 WL 5379379, at *2.

The Court then unequivocally stated that “the any-exposure opinion is simply unsupportable both as a matter [of] law and science.” Id. at *3.  It concluded that the “theory that each and every exposure, no matter how small, is substantially causative of disease may not be relied upon as a basis to establish substantial-factor causation for diseases that are dose-responsive.”  Id. at *2.

The litigation began when John C. Ravert sued several companies in the Court of Common Pleas of Philadelphia in 2007, alleging that he developed mesothelioma after exposure to defendants’ asbestos-containing products at several work sites.  The Court of Common Pleas granted summary judgment for the defendants, holding that Mr. Ravert failed to establish that he breathed asbestos-containing dust from products manufactured or distributed by the defendants.

On appeal, the Superior Court reversed the decision and held that plaintiffs’ experts had sufficiently established a material issue of fact as to whether dust from the defendants’ products was a substantial factor in causing Mr. Ravert’s mesothelioma. The Pennsylvania Supreme Court reversed this decision and reinstated the order granting summary judgment. 

This case is an important addition to the growing consensus that the “every breath” theory is invalid.  It also serves as a useful guide for litigants with respect to several important precepts governing the admissibility of expert testimony regarding dosage and exposure in asbestos litigation.