Civil penalties (a) Assessment of penalties Any person organizing an expedition that the Director determines, after notice and an opportunity for a hearing, to have failed to comply with the requirements of this subtitle, or its implementing regulations, shall be liable to the United States for a civil penalty. The amount of the civil penalty shall not exceed $125,000 for each violation unless the prohibited act was knowingly committed, in which case the amount of the civil penalty shall not exceed $250,000 for each violation. Each day an expedition remains in Antarctica without complying with the requirements of this subtitle shall constitute a separate offense for penalty purposes. The amount of any civil penalty shall be assessed by the Director by written notice. Any civil penalty assessed under this subsection may be remitted or mitigated by the Director. (b) Hearings Hearings for the assessment of civil penalties under subsection (a) shall be conducted in accordance with section 554 of title 5, United States Code. For the purposes of conducting any such hearing, the Director may issue subpoenas for the attendance and testimony of witnesses and the production of relevant papers, books, and documents, and may administer oaths. Witnesses summoned shall be paid the same fees and mileage that are paid to witnesses in the courts of the United States. In case of contumacy or refusal to obey a subpoena served upon any person pursuant to this subsection, 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 Director or to appear and produce documents before the Director, or both, and any failure to obey such order of the court may be punished by such court as a contempt thereof. (c) Review Upon the failure of any person against whom a civil penalty is assessed under subsection