One of the distinct characteristics of asbestos is that prolonged exposure often results in multiple diseases, both benign and malignant, that can develop at different times in someone’s life. This characteristic has proven uniquely challenging in the context of asbestos litigation.

Until 1992, Pennsylvania was considered a “one disease” state, which meant that plaintiffs were required to bring all possible asbestos claims relating to the same exposure in one lawsuit. Under this rule, the statute of limitations on all claims relating to asbestos exposure began to run when a plaintiff was first diagnosed with an asbestos related disease. The practical implications of such a rule meant that a plaintiff who was diagnosed with a nonmalignant asbestos disease was required to include claims relating to fear of developing cancer in the future within the same lawsuit. 

This all changed in 1992 when the Pennsylvania Superior Court decided the case of Marinari v. Asbestos Corp. Ltd., 612 A.2d 1021 (Pa.Super. 1992). This case established a “separate disease” rule in Pennsylvania, allowing a plaintiff who had previously brought a claim for a nonmalignant asbestos related disease to later bring another claim for a separate asbestos-related cancer arising out of the same exposure. The Mariani ruling has effectively eliminated the need to include claims relating to fear of developing cancer. Mariani has also allowed plaintiffs who have been diagnosed with an asymptomatic asbestos related disease to forgo filing a lawsuit until they are later diagnosed with a more serious disease.

While the Mariani ruling clearly applies to cases where a plaintiff develops asbestos-related cancer after previously bringing a claim for a nonmalignant asbestos related disease, it has yet to be extended to a situation where a plaintiff develops asbestos-related lung cancer after previously bringing a claim for a separate form of asbestos-related cancer such as mesothelioma. The Pennsylvania Supreme Court recently heard argument on this issue in the case of Daley v. A.W. Chesterton, but has yet to make a ruling.