The federal Resource Conservation and Recovery Act (“RCRA”) authorizes a citizen suit against “any person” who has violated “any permit, standard, regulation, condition, requirement, prohibition, or order which has become effective pursuant to this chapter,” or “who has contributed or who is contributing to the past or present handling, storage, treatment, transportation, or disposal of any solid or hazardous waste which may present an imminent and substantial endangerment to health or the environment.” 42 U.S.C. § 6972(a)(1). Disputes between private ...