; and (B) conduct, on a non-reimbursable basis, an investigation or an evidentiary hearing, necessary to assess the cost of the response action that should have been taken in the case of an environmental emergency caused by the operator’s ship-based activities, including any determination concerning the underlying response activity and to submit to the Director proposed findings of fact and recommendations for adjudication by the Director. (5) With regard to any investigation or evidentiary hearing conducted pursuant to clause (iv), the Director is authorized to delegate, to the Commandant, the authority, set forth in clause (ii), to issue subpoenas and administer oaths, and to pay fees and mileage. In case of contumacy or refusal to obey a subpoena served upon any person pursuant to this clause, the district court of the United States for any district in which such person is found, resides, or transacts business, upon application by the United States and after notice to such person, shall have jurisdiction to issue an order requiring such person to appear and give testimony before the agency head or to appear and produce documents before the agency head, and any failure to obey such order of the court may be punished by such court as a contempt thereof. (6) The Director shall not commence an administrative proceeding in accordance with clauses (i) and (ii) of this section later than 15 years after the United States Government becomes aware of the environmental emergency. (7) Upon the failure of any operator against whom costs have been assessed under this section to pay such costs, the Director may request the Attorney General to institute a civil action in a district court of the United States for any district in which such person is found, resides, or transacts business to collect the costs and such court shall have jurisdiction to hear and decide any such action. The court shall hear such action on the record made before the Director pursuant to this section and shall sustain the Director’s decision if it is