Liability policy limits are usually based on occurrences, with a new limit applied to each occurrence and an annual limit on top of that. (This may not apply in claims made policies which are usually issued to professionals) As a result, insurance companies are often litigating whether an incident is one or multiple occurrences. For example if a car goes out of control and hits one car, then another, are there two occurrences or just one? Usually, these multiple impact cases are treated as one occurrence.
In Hollis v. Lexington, (unpublished), Hollis claimed numerous acts of negligence by the fireworks company and its employees which resulted in injuries to Hollis and her sons when a misfired firework exploded near them. The insurance policy had limits of 1 million per occurrence and $2 million in the aggregate. But since the cause of the injury was one thing — the exploding firework — there was only one occurrence, and thus, only one limit of insurance applied.