Any person subject to section
of this title who is found by the Administrator, after notice and an opportunity for a hearing in accordance with section
, to have committed any act prohibited by section
of this title shall be liable to the United States for a civil penalty. The amount of the civil penalty shall not exceed $25,000 for each violation. Each day of a continuing violation shall constitute a separate offense. The amount of such civil penalty shall be assessed by the Administrator by written notice. In determining the amount of such penalty, the Administrator shall take into account the nature, circumstances, extent, and gravity of the prohibited act committed and, with respect to the violator, any history of prior offenses, good faith demonstrated in attempting to achieve timely compliance after being cited for the violation, and such other matters as justice may require.