Richard Wolf

USA TODAY

WASHINGTON — The question was who should pay for air pollution that crosses state lines. The answer, the Supreme Court ruled Tuesday, is blowing in the wind.

States in the Midwest and South whose polluted air flows north and east must comply with a federally imposed solution, a 6-2 majority of justices ruled.

The decision, written by Justice Ruth Bader Ginsburg and joined by two of the court's conservatives, was a boon for the Obama administration and its environmental regulators. They had required 28 upwind states to slash ozone and fine particle emissions from power plants because of their downwind effects.

Most of those states had rebelled against the solution, and a federal appeals court sided with them in 2012. But the justices reversed the lower court's ruling.

The case focuses on air currents miles overhead but has down-to-earth consequences. The Environmental Protection Agency blames exposure to ozone and fine particles in the air for one in 20 deaths in the United States, 90,000 hospital admissions, 200,000 non-fatal heart attacks and 2.5 million cases of aggravated asthma.

Given the depth of the problem, the court majority concluded that the EPA chose a sensible solution -- basing required reductions in pollutants that cause soot and smog on the least costly means available. That puts an added burden on states that have done less in the past to control their power plant pollution.

"We are satisfied that EPA's construction of the (Clean Air Act) reasonably responded to a perplexing problem the statute itself does not resolve," Ginsburg said from the bench.

Attorneys for the objecting states and industries argued that the EPA was imposing a solution on the states before they could devise their own emissions control plans.

It's known as the "good neighbor" provision, but the neighbors haven't been playing nice. Twenty-four states had urged the justices to uphold the federal appeals court ruling striking down the EPA rule. Nine states and six cities had asked them to reverse the appeals court decision and reinstate the rule.

Justice Antonin Scalia dissented from the ruling along with Justice Clarence Thomas, arguing that upwind states should be responsible only for their proportional share of downwind pollution. He said the decision will create "government by the bureaucracy" and feed "the uncontrolled growth of the administrative state at the expense of government by the people."

The high court first dealt with the issue of cross-state air pollution in 1907, when Justice Oliver Wendell Holmes ruled against two copper smelters in Tennessee for the "wholesale destruction of forests, orchards and crops" in Georgia. In 1963, Congress passed the Clean Air Act, the nation's most powerful tool against air pollution, and has updated it several times since.

The cross-state transport rule was born in 1977 and tightened in 1990, but federal regulators never have been able to make it work. The most recent effort set tough standards for "upwind" states and their polluting industries, mostly coal- and oil-fired power plants.

A three-judge panel of the U.S. Court of Appeals for the D.C. Circuit struck that down last year. It ruled that the EPA didn't give states enough time to devise their own emissions reduction plans and didn't limit the fix to each state's "significant contribution" to the overall problem.

But the court's majority ruled that with air pollution blowing in the wind, it would be impossible to apportion blame precisely, making a federal solution based on costs and other factors more palatable.

"The proportional approach, EPA persuades us, works neither mathematically nor in practical application," Ginsburg said. "Proportionality as to one downwind state will not yield proportionality as to others."

The justices also noted that Mid-Atlantic and Northeast states cannot meet federal emissions control standards without help from their neighbors to the west and south. Maryland, which spent $2.6 billion on its own emissions control efforts between 2007-10, estimates that 70% of its air pollution floats in over its borders.

Ginsburg was joined in the decision by Chief Justice John Roberts and Justices Anthony Kennedy, Stephen Breyer, Sonia Sotomayor and Elena Kagan. Justice Samuel Alito had recused himself from the case, presumably because of a potential conflict of interest.

Environmental groups hailed the decision. EPA Administrator Gina McCarthy called it "a resounding victory for public health" that "serves to support the ongoing work to see that air quality in downwind states continues to improve."

Industry groups were warned that the ruling would impose new costs on power plants, possibly forcing some to shut down.

"EPA continues to abuse the Clean Air Act, imposing overreaching regulations that promise little gain with great pain for American consumers and the broader American economy," said Laura Sheehan of the American Coalition for Clean Coal Electricity.

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