Do air emissions of hazardous substances create a cleanup liability under the Superfund? In the closely watched case of Pakootas, et al. v. Teck Cominco Metals, Ltd., 1 the Ninth Circuit said, "no," becoming the highest court to rule upon this novel theory of liability under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).

The decision is the latest iteration of a long-running dispute over a smelter located approximately ten miles north of the Canadian border in British Columbia. Previously, plaintiffs Washington State and an Indian tribe won a precedential decision that a foreign-based facility can be held liable under CERCLA for discharging slag in a river that crosses into the United States. Plaintiffs then amended their complaint to allege that the facility also arranged for disposal under CERCLA by emitting hazardous air emissions from its smokestacks to be carried by the wind and deposited on the Upper Columbia River Superfund Site in Washington. The district court denied Teck Cominco's motion to dismiss, finding that the air emissions constituted a "disposal" under CERCLA when they touched down on land or water. The issue was certified for immediate appellate review because of its important precedent.

The Ninth Circuit first found that the aerial deposition theory appeared to be "a reasonable enough construction" based on the plain language of the statute, with no contrary guidance in legislative history or the EPA's interpretations. However, the Court concluded it was not writing on a blank slate. Noting that CERCLA incorporates the definition of "disposal" from the Resource Conservation and Recovery Act (RCRA), the Court cited its prior decision in Ctr. for Cmty. Action and Envtl. Justice v. BNSF Rwy. Co., 2 which held that diesel particulate emissions "transported by wind and air currents onto the land and water" did not constitute "disposal" of waste within the meaning of RCRA. To be a disposal, the solid or hazardous waste must firstbe placed into or on any land or water and thereafter be emitted into the air. The Court also cited its en banc decision in Carson Harbor Vill., Ltd. v. Unocal Corp., 3 where passive migration was not a disposal under CERCLA. Those decisions found that Congress intended that "disposal" or "deposit" in RCRA and CERCLA means contamination caused by active human intervention and not passive processes.

The Court stated this definition of "disposal" was largely consistent with CERCLA's overall statutory scheme. The Court expressed concern that plaintiffs' interpretation would stretch CERCLA liability beyond the bounds of reason. "[I]f 'aerial depositions' are accepted as 'disposals,'" the Court said, "'disposal' would be a never-ending process, essentially eliminating the innocent landowner defense."

The Ninth Circuit's decision creates important precedent excluding air emissions from the reach of CERCLA. Under the Clean Air Act and state laws, such emissions are regulated under a complex regulatory and permit scheme. The attempt to graft CERCLA or RCRA onto this scheme and impose additional liability for the costs of responding to the "disposal" of hazardous substances would have created complexities and conflicts for regulated parties seeking to comply with the law.


1 No. 15-35228 (July 27, 2016), available at

2 764 F.3d 1019 (9th Cir. 2014).

3 270 F.3d 863 (9th Cir. 2001).

Because of the generality of this update, the information provided herein may not be applicable in all situations and should not be acted upon without specific legal advice based on particular situations.

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