Read the policy. Understand what it says. The United States 5th Circuit issued a 1998 opinion that shows how courts will interpret policies. The style of the case is, Lubbock County Hospital District v. National Union Fire Insurance Company of Pittsburg. Here is some relevant information from the case.
Approximately 1,000 gallons of fuel escaped from the fueling system at University Medical Center’s helipad. UMC sued Rocky Mountain Helicopters, Inc., the operators, for the costs of clean up and monitoring. UMC recovered a judgment of nearly $500,000 against Rocky Mountain.
UMC brought suit against National Union seeking a declaration that the insurance policy it issued to Rocky Mountain covered damages for the fuel spill. National Union removed the case to Federal District Court on the basis of diversity. Both parties filed motions for summary judgment. The district court granted summary judgment in favor of UMC finding coverage under two endorsements to the policy.