CERCLA was designed to promote the ''timely cleanup of hazardous waste sites'' and to ensure that the costs of such cleanup efforts were borne by those responsible for the contamination. Brown & Bryant, Inc. (B&B), began operating an agricultural chemical distribution business, purchasing pesticides, and other chemical products from suppliers such as Shell (D). Using its own equipment, B&B applied its products to customers' farms. B&B operated on a 3.8-acre parcel of former farmland and expanded operations onto an adjacent .9-acre parcel of land owned jointly by Burlington (D). The land was graded toward a sump and drainage pond located on the southeast corner of the primary parcel. Neither the sump nor the drainage pond was lined until 1979, allowing wastewater and chemical runoff from the facility to seep into the groundwater below. B&B purchased pesticides D-D and Nemagon, both sold by Shell (D). D-D was stored in 55-gallon drums and 5-gallon containers on a concrete slab outside B&B's warehouse. Nemagon was stored in 30-gallon drums and 5-gallon containers inside the warehouse. Shell (D) began requiring its distributors to maintain bulk storage facilities for D-D. From that time onward, B&B purchased D-D in bulk. Arriving product was transferred from tanker trucks to a bulk storage tank and then transferred to bobtail trucks, nurse tanks, and pull rigs. Leaks and spills were commonplace. Shell (D) eventually required distributors to obtain an inspection by a qualified engineer and provide self-certification of compliance with applicable laws and regulations. Despite improvements, B&B remained a ''sloppy' operator.' California began investigating B&B's violation of hazardous waste laws, and P soon followed suit, discovering significant contamination of soil and groundwater. B&B become insolvent and ceased all operations. P ordered Burlington (D) to perform certain remedial tasks in connection, which cost more than $3 million. Burlington (D) brought suit against B&B, and that lawsuit was consolidated with two recovery actions brought by P against Shell (D) and Burlington (D). The court held that both Ds were potentially responsible parties under CERCLA. It concluded that the harm was divisible and therefore capable of apportionment. Burlington (D) was found liable for 9% and Shell (D)for 6% of the total site response cost.
P appealed the apportionment, and Shell (D) cross-appealed the court's finding of liability. The Court of Appeals held that Shell (D) could still be held liable under a ''broader' category of arranger liability' if the 'disposal of hazardous wastes was a foreseeable byproduct of, but not the purpose of, the transaction giving rise to' arranger liability. Thus, an entity could arrange for 'disposal' 'even if it did not intend to dispose' of a hazardous substance. The Supreme Court granted certiorari to determine whether Shell (D) was properly held liable as an entity that had 'arranged for disposal' of hazardous substances within the meaning of § 9607(a)(3), and whether Shell (D) and Burlington (D). were properly held liable for all response costs incurred by Ps.