556 U.S. 599 (2009)
Burlington Northern & Santa Fe Railway Co. v.
1) Does arranger liability under CERCLA §107(a)(3) attach to a seller of a useful product who knows spills will occur during the buyer's handling, absent intent to dispose? 2) May PRPs avoid joint and several liability by proving a reasonable basis for apportioning a single, commingled harm, and was the district court's 9% apportionment to the railroads permissible?
Arranger liability under CERCLA §107(a)(3) requires that the defendant intended to dispose of a hazardous substance; mere knowledge that spills may occur in the course of selling a useful product is insufficient. Joint and several liability is not automatic under CERCLA. Applying common-law principles of apportionment (e.g., Restatement (Second) of Torts §433A), a defendant is severally liable only for the portion of harm it proves is reasonably capable of division; a reasonable basis for estimating the contribution to a single harm will suffice, even if the calculation is imprecise.
The Supreme Court held that Shell was not liable as an arranger because it did not intend to dispose of a hazardous substance in selling D-D. The Court further held that the harm at the B&B site was reasonably capable of apportionment and that the district court's 9% apportionment of total response costs to the railroads had an adequate evidentiary basis. The Ninth Circuit's judgment was reversed.
This case reshaped CERCLA litigation in two ways. First, it narrowed arranger liability by imposing an intent requirement, reducing exposure for upstream sellers of useful products and curbing expansive theories based on mere knowledge or foreseeability of spills. Second, it reaffirmed that PRPs can limit liability through apportionment upon a reasonable showing of divisibility, thereby preventing solvent defendants from automatically bearing orphan shares when other PRPs are insolvent. For law students, the case is essential for understanding the interplay between statutory text, common-law principles of causation and damages, and strategic proof in complex environmental cost-recovery actions.