EPA, Advocates Tussle Over Scope of Ozone ‘Backsliding’ Action

The EPA took the stand Monday to defend the lift of “backsliding” air quality measures, a decision targeted by environmentalists who want to keep heavy ozone pollution under the strictest standards possible.

A panel at the U.S. Court of Appeals for the District of Columbia Circuit grappled with arguments in Sierra Club v. EPA, a lawsuit brought by advocates who claim the agency cannot scrap backsliding provisions—even for revoked National Ambient Air Quality Standards—without first designating the area under “attainment” of national standards.

The Sierra Club sued the Environmental Protection Agency after it revoked backsliding measures for Dallas and ...