Determining the date of an occurrence, that is when an injury can be said to have occurred, can cause a dispute over which insurance policy applies to a claim or lawsuit.

There is a general rule that applies for determining when an occurrence happens, as stated by the United States Court of Appeals, Third Circuit, in Appalachian Insurance Co. v. Liberty Mutual Insurance Co., 676 F.2d 56 (1982): “There can be no question but that the aspect of the occurrence that must take place within the policy period is the result, that is, the time when the accident or injurious exposure produces the personal injury.” However, when is the actual time when the accident produces the injury and thus, the insurance coverage?

There is a more comprehensive discussion of the theories and multiple cases pertaining to the theories, in Armstrong World Industries v. Aetna Casualty & Surety Co., 26 Cal. Rptr.2d 35 (1993). Although the opinion in this case was superseded by the California Supreme Court in In re Asbestos Insurance Coverage Cases, 866 P.2d 1311 (1994), the discussion of the theories and the cases listed are still worth reading.

When did the injury occur?

When it comes to the timing of bodily injury and property damage, the following information is generally true. Courts have accepted four major theories as to when bodily injury can be said to have occurred: the exposure theory; the manifestation theory; the triple-trigger theory; and the injury-in-fact theory. As for property damage, the prevailing rule is that property damage occurs at the time the damage is discovered or when it has manifested itself, although some courts today are applying a different way of thinking.