The Secretary may also obtain review or enforcement of any final order of the Commission by filing a petition for such relief in the United States court of appeals for the circuit in which the alleged violation occurred or in the Court of Appeals for the District of Columbia Circuit, and the provisions of subsection (a) shall govern such proceedings to the extent applicable. If no petition for review, as provided in subsection (a) of this section, is filed within 30 days after issuance of the Commission’s order, the Commission’s findings of fact and order shall be conclusive in connection with any petition for enforcement which is filed by the Secretary after the expiration of such 30-day period. In any such case, as well as in the case of a noncontested citation or notification by the Secretary which has become a final order of the Commission under subsection (a) or (b) ofsection
of this title, the clerk of the court, unless otherwise ordered by the court, shall forthwith enter a decree enforcing the order and shall transmit a copy of such decree to the Secretary and the operator named in the petition. In any contempt proceeding brought to enforce a decree of a court of appeals entered pursuant to this subsection or subsection (a) of this section, the court of appeals may assess the penalties provided in section
of this title, in addition to invoking any other available remedies.