Code of Federal Regulations Title 33. Navigation and Navigable Waters § 33.25.803 Claims payable

(a) Caused by the United States, its employees, agents or contractors during containment, countermeasures, cleanup, mitigation, and disposal activities under the National Contingency Plan;  and

(b) In the exercise of care reasonable under the circumstances, the incident giving rise to the claim was necessary and the damage unavoidable.