(a) General. - At the request of the Secretary of Transportation, the Attorney General may bring a civil action in an appropriate district court of the United States to enforce this chapter or a regulation prescribed or order issued under this chapter.

The court may award appropriate relief, including punitive damages. (b) Imminent Hazards. - (1) If the Secretary has reason to believe that an imminent hazard exists, the Secretary may bring a civil action in an appropriate district court of the United States - (A) to suspend or restrict the transportation of the hazardous material responsible for the hazard; or (B) to eliminate or ameliorate the hazard. (2) On request of the Secretary, the Attorney General shall bring an action under paragraph (1) of this subsection. (c) Withholding of Clearance. - (1) If any owner, operator, or individual in charge of a vessel is liable for a civil penalty under section 5123 of this title or for a fine under section 5124 of this title, or if reasonable cause exists to believe that such owner, operator, or individual in charge may be subject to such a civil penalty or fine, the Secretary of the Treasury, upon the request of the Secretary, shall with respect to such vessel refuse or revoke any clearance required by section 4197 of the Revised Statutes of the United States (46 App. U.S.C. 91). (2) Clearance refused or revoked under this subsection may be granted upon the filing of a bond or other surety satisfactory to the Secretary.