On August 20, 2014, the US Court of Appeals for the Ninth Circuit affirmed the dismissal of a suit brought by environmental groups against Union Pacific Corp. and BNSF Railway Co., holding that the Resource Conservation and Recovery Act (RCRA) does not authorize a citizen suit to enjoin the emission of diesel particulate matter as it does not constitute “disposal” of a “solid waste” under RCRA.

Three environmental groups sued the rail yard operators under RCRA’s citizen-suit provision, asking the district court to declare defendants’ activities in violation of RCRA and order the defendants to take certain control measures to reduce diesel particulate emissions from their rail yards. The environmental groups alleged that the defendants “dispose” of “solid waste” by “allowing [diesel particulate matter] to be transported by wind and air currents onto the land and water near the railyards.” The district court dismissed the suit with prejudice, concluding that the Clean Air Act (CAA), not RCRA, applies to diesel particulate matter emissions and that, even if RCRA did apply, diesel exhaust is not a solid or hazardous waste.

In affirming the district court’s decision, the Ninth Circuit held that even if the factual allegations are true, they do not establish that the defendants “dispose” of solid waste as defined under RCRA. Rather, the panel concluded the opposite of plaintiffs’ allegation is true: “disposal” occurs where a solid waste is first placed into or on any land or water and is thereafter emitted into the air. It does not extend to emissions of solid waste directly into the air. In support of its conclusion, the court observed that RCRA’s definition of “disposal” – i.e., “the discharge, deposit, injection, dumping, spilling, leaking, or placing … into any or on any land or water” – does not mention “emitting” or any like terms but certain other RCRA terms and provisions do. That Congress knew how to define “disposal” to include emissions but chose not to do so, supported the panel’s decision not to read “disposal” as including air emissions.

The environmental groups also argued that because RCRA has an “air emissions” provision for the monitoring and control of air emissions at certain facilities, air emissions must fall within RCRA’s reach and form the basis of a citizen suit. The Ninth Circuit flatly rejected this assertion stating that, while certain air emissions fall within RCRA’s reach, it does not provide a private right of action.

The Ninth Circuit also rejected the environmental groups’ argument that there is an irreconcilable conflict between the CAA and RCRA. Rather, the panel found that the statutes’ legislative histories clearly evince that RCRA governs land disposal while the CAA governs air pollutants. It also found further support against the environmental groups’ claim of statutory conflict because defendants’ rail yards, as “indirect sources” of air pollution, are excluded from both regulatory schemes. The panel declined the environmental groups’ invitation to fill what they called a “regulatory gap” between the CAA and RCRA. Instead, the panel affirmed the district court’s finding that any “gap” is the product of a careful and reasoned decision made by Congress that the Ninth Circuit would not and could not disturb.