The district court shall have jurisdiction in actions brought under subsection (a) against an owner or operator of a facility to enforce the requirement concerned and to impose any civil penalty provided for violation of that requirement. The district court shall have jurisdiction in actions brought under subsection (a) against the Administrator to order the Administrator to perform the act or duty concerned.
No action may be commenced under subsection (a) against an owner or operator of a facility if the Administrator has commenced and is diligently pursuing an administrative order or civil action to enforce the requirement concerned or to impose a civil penalty under this Act with respect to the violation of the requirement.
The court, in issuing any final order in any action brought pursuant to this section, may award costs of litigation (including reasonable attorney and expert witness fees) to the prevailing or the substantially prevailing party whenever the court determines such an award is appropriate. The court may, if a temporary restraining order or preliminary injunction is sought, require the filing of a bond or equivalent security in accordance with the Federal Rules of Civil Procedure.
In any action under this section, any person may intervene as a matter of right when such person has a direct interest which is or may be adversely affected by the action and the disposition of the action may, as a practical matter, impair or impede the person’s ability to protect that interest unless the Administrator or the State shows that the person’s interest is adequately represented by existing parties in the action.