The U.S. Supreme Court’s decision in Burlington Northern Santa Fe Railway Co. v. United States, 129 S. Ct. 1870 (2009), examined two unsettled areas of CERCLA: (1) the proof necessary to establish whether a PRP has “arranged for the disposal or treatment… of hazardous substances…”; and (2) CERCLA apportionment, i.e., whether a PRP is jointly and severally liable for an entire site, or rather only severally liable for a portion of the site. 
In an article on Lexology titled, “Four Years Later: How Has BNSF Changed CERCLA Practice?”, posted on November 20, 2012, Anthony G. Hopp and Colin O’Donovan of Edwards Wildman and Paul S. Kline of Three Rivers Management, Inc., explore the ramifications of the BNSF decision.