The Ninth Circuit’s recent opinion in Pakootas v. Teck Cominco Metals, Ltd., addressed whether, “[w]hen a smelter emits lead, arsenic, cadmium, and mercury compounds through a smokestack and those compounds contaminate land or water downwind, . . . the owner-operator of the smelter [can] be held liable for cleanup costs and natural resource damages under the Comprehensive Environmental Response, Compensation, and Liability Act (‘CERCLA’).” In its anxiously awaited decision, the Court rejected the plaintiffs’ theory that such aerial emissions constitute an actionable disposal under CERCLA.

The dispute in Pakootas revolves around alleged damage in the State of Washington related to the operation of Defendant Teck Cominco Metals, Ltd.’s smelter (the “Cominco Smelter”), located just north of the US-Canada border. Plaintiffs’ amended complaint raised CERCLA claims based on alleged contamination that originated from the smoke stacks at the Cominco Smelter and “travelled [sic] through the air into the United States resulting in the deposition of airborne hazardous substances into the Upper Columbia River Site.” Plaintiffs’ novel argument that smoke stack emissions create CERCLA liability is likely a result of the unique circumstance in which emissions occurring in Canada are not subject to US regulation at the source.

After initially denying the defendant’s motion to dismiss claims based on emissions, the district court certified the question to the Ninth Circuit, explaining that, during the more than 30 years since CERCLA was enacted, no court has addressed the application of CERCLA to aerial emissions. At the Ninth Circuit, plaintiffs argued that smelter emissions that make their way to land or water constitute the “deposit” of hazardous substances, which is one of the verbs used to define disposal under 42 U.S.C. § 6903(3). The definitions of “deposit” cited by plaintiffs “refer to natural forces slowly depositing layers of dirt or mud over time.”

Defendant argued, however, that the Clean Air Act, not CERCLA, “comprehensively regulates the emissions of particulate matter and other contaminants.” Interpreting CERCLA to address aerial emissions undermines the balance struck by Congress, including allowing extensive civil liability not intended under the Clean Air Act.

In its decision, the Court acknowledged that plaintiffs’ aerial deposition theory was “reasonable enough.” However, the Court also noted that it does not “write on a blank slate” and is bound to consider prior Ninth Circuit precedent which militates against the plaintiffs’ theory of disposal. In Carson Harbor Village, Ltd. v. Unocal Corp., the court determined that “disposal” does not encompass “passive migration.” And, in Center for Community Action & Environmental Justice v. BNSF Railway Co., the Ninth Circuit held that emissions of diesel particulate matter into the air did not constitute disposal of waste within the meaning of the Resource Conservation and Recovery Act (“RCRA”). The court was especially persuaded by the holding in Center for Community Action, as CERCLA incorporates the RCRA definition of “disposal.”

In addition to the weight of prior precedent, the court reasoned that there was no contrary legislative history, no intervening supreme court decision, and no agency definition of deposit or disposal—in a regulation or regulatory guidance—to which the court might owe deference. Although plaintiffs’ construction was “arguably plausible,” the decisions in Carson Harbor and Center for Community Action compelled the court to exclude smelter emissions from the scope of CERCLA liability.