The U.S. Supreme Court on Tuesday grappled with the extent to which—if at all—a federal agency must review the downstream environmental effects of a proposed infrastructure project when those impacts are neither directly caused by the project nor fall within the agency's jurisdiction under the National Environmental Policy Act.

Attorney Paul Clement, pressing for a narrow reading of NEPA, told the justices that the Surface Transportation Board has no statutory obligation to study the environmental harm that a proposed 88-mile rail line may cause as a result of its intended cargo, waxy crude oil destined for a refinery. Such concerns are remote in time and space and are the province of agencies that regulate refineries, Clement said.