Business interruption insurance claims arising from the Sept. 11 terrorist attacks involve a variety of unique, gray areas that will keep some claims dragging on for years before being settled, according to an international consulting firm's study.

Business interruption claims will account for more than a quarter of the insurance claims to arise from the Sept. 11 events, according to the report released today by PricewaterhouseCoopers in New York. The company said such claims stretch across the financial services, communications, media and travel industries.

PWC noted that business interruption coverage generally requires "direct physical loss or damage to the property," and is written to cover loss of gross earnings, which "result from interruption of or interference with the business, and caused by loss to real or personal property."