the costs amongst themselves, and other unnamed, but responsible parties. The rationale for joint and several liability is to create an incentive for named PRPs to search out other PRPs, so as to make all responsible polluters pay for cleanups. Sarah W. Rubinstein, CERCLA’s Contribution to the Federal Brownfields Problem: A Proposal for Federal Reform, 4 U. Chi. Sch. Roundtable 149, 152 (1997). Although there are circumstances under which municipalities may be considered PRPs under CERCLA’s liability scheme, see, e.g., City of Fresno v. NL Indust., 1995 WL 641983 (E.D.Cal.1995), it is not clear whether a municipality may be considered a PRP solely as a result of operating a municipal sewer system. Compare Lincoln Prop., Ltd. v. Higgins, 823 F.Supp. 1528, 1538, 1539-44 (E.D.Cal.1992) (<HOLDING>), with Westfarm Assoc. Ltd. P’ship v.
holding that releases between tortfeasors to avoid liability under cercla are not valid holding that state law determines successor liability under cercla holding that a municipal sewer system that leaked hazardous waste could rely on a thirdparty defense to avoid liability under cercla recognizing cercla successor liability holding that a municipal sewer system is liable for the acts of a third party that discharged hazardous waste into the system