In a much anticipated ruling, the Philadelphia Court of Common Pleas barred plaintiffs' experts in three asbestos cases from offering testimony that "each and every exposure to asbestos" is a substantial contributing factor in asbestos-related toxic tort actions. The Frye hearing arose from a Motion for a Frye Hearing filed by Defendant Chrysler LLC and joined in by Defendants Ford Motor Company, General Motors Corporation and Honeywell Corporation. The court's decision pertains specifically to three asbestos cases: Caswell v. A.W. Chesterton, Inc., et al., 0609-0782; Duke v. Chrysler LLC, et al., 0612-3451; and Fisher v. A.O. Smith Corp., et al., 0608-2483.

The ruling may significantly weaken a plaintiff's claims against tertiary asbestos defendants, such as automobile companies and other friction materials manufacturers.