WASHINGTON — The
Supreme Court heard arguments Tuesday in a knotty environmental case over how to hold states responsible for air pollution that drifts across their borders and causes harm in downwind states.
If there was consensus among the justices, it concerned only the complexity and difficulty of the issues before them.
“This is a tough problem,” said Justice Stephen G. Breyer.
A few minutes later, Justice Elena Kagan offered a similar assessment. “This is a hard problem,” she said.
The Obama administration’s solution, a trading system in which the states could buy and sell pollution credits, was struck down last year in a 2-to-1 ruling from the US Court of Appeals for the District of Columbia.
The appeals court said that the Environmental Protection Agency had exceeded its authority under the Clean Air Act in the way it apportioned the cleanup work among 28 upwind states.
The air in those states, mostly in the Midwest and South, may meet regulatory standards within their borders even as pollutants from their power plants and refineries drift across state lines, preventing neighboring states from meeting their legal obligations.
The affected states are largely in the Northeast and the mid-Atlantic.
The regulation at issue, the Cross-State Air Pollution Rule, did not apportion reductions by the amount of pollution contributed by each upwind state. Instead, the agency sought to encourage remedial action where it was cheapest.
The appeals court said this approach violated the Clean Air Act’s “good neighbor” provision by requiring upwind states “to reduce their emissions by more than their own significant contribution” to downwind pollution.