Redoil v. EPA

The Clean Air Act is ambiguous regarding whether best available control technology applies to support vessels; as a result, an Environmental Appeals Board interpretation of the statute deserves deference under Chevron U.S.A., Inc. v. NRDC, Inc.

Resisting Environmental Destruction on Indigenous Lands, with other environmental groups (REDOIL) challenged two permits issued by the Environmental Protection Agency (EPA) to Shell Gulf of Mexico, Inc. and Shell Offshore, Inc. (Shell). The permits allow Shell to operate a drillship and fleet off the North Slope of Alaska. The permits limit specific emissions pursuant to the Clean Air Act “best available control technology” (BACT) limits, but only for the drillship and supply vessels tied to it. REDOIL appealed the permits, arguing restrictions apply to any vessel operating within 25 miles of the drillship. The Environmental Appeals Board (EAB) denied review. Revised permits issued by the EPA exempted a 500-meter radius from “ambient air” standards, contingent on the establishment of a safety zone and other public access requirements. REDOIL again appealed, challenging the exception, and EAB dismissed the appeal. REDOIL sought review of both EAB decisions. The Court found the drillship is an “Outer Continental Shelf source” pursuant to a plain reading of the statute, subject to BACT limits. The Court also found Congress did not intend support vessels unattached to the OSC source be regulated because they are not OSC sources themselves. In addition, the Court interpreted the statute to distinguish between stationary and mobile sources, upholding the EAB ruling that BACT does not apply to vessels moving freely. The Court held the Act is ambiguous regarding vessels unattached to the OSC source, and focused on EPA's reasonableness in interpreting the statute. The Court deferred to the EPA, and agreed BACT does not apply to mobile, unattached vessels. The Court held the grant of the 500 meter ambient air exception was not “plainly erroneous” and was, in fact, consistent with agency regulation, and the condition of an effective safety zone is a permissible interpretation. PETITION DENIED.