An action for recovery of removal costs referred to in section
2702
(b)(1) of this title must be commenced within 3 years after completion of the removal action. In any such action described in this subsection, the court shall enter a declaratory judgment on liability for removal costs or damages that will be binding on any subsequent action or actions to recover further removal costs or damages. Except as otherwise provided in this paragraph, an action may be commenced under this subchapter for recovery of removal costs at any time after such costs have been incurred.