Dist. Ct. erred in dismissing as untimely plaintiffs’ (Trustees of environmental trust fund) action under 9607(a) of CERCLA seeking environmental cleanup costs incurred pursuant to 2002 Administrative Order of Consent (AOC) that required defendants to fund work called for by Enforcement Action Memorandum. Dist. Ct. improperly viewed plaintiffs’ action as essentially contribution claim under section 9613(f) of CERCLA and wrongfully applied 3-year limitation period under section 9613(g) since plaintiffs had not previously been subjected to any civil action under section 9606 or 9607 of CERCLA, which would be required to establish contribution claim under section 9613(f). In defendants’ petition for rehearing, Ct. rejected claim that plaintiffs were limited to contribution action (as opposed to cost recovery action) for costs incurred pursuant to 2002 AOC.