WASHINGTON—The U.S. Supreme Court on Monday rejected federal environmental regulations requiring power plants to limit emissions of mercury and other pollutants, in a defeat for the Obama administration.
In a 5-4 decision split along conservative and liberal lines, the court sided with 23 states and industry groups who had protested the cost of standards imposed in 2012 by the national Environmental Protection Agency (EPA).
On the last day of its annual session, the Supreme Court said the EPA had "interpreted unreasonably when it deemed cost irrelevant to the decision to regulate power plants."
The plaintiffs in the case had complained about the "huge costs" required to comply with the standards.
The EPA had estimated its regulations would cost $9.6 billion a year, but the court found this amount far outstripped the "quantifiable benefits" from the resulting reduction in emissions.
"It is not rational, never mind 'appropriate,' to impose billions of dollars in economic costs in return for a few dollars in health or environmental benefits," Justice Antonin Scalia wrote in the majority ruling.
In her dissenting opinion, Justice Elena Kagan wrote that the regulations would have saved a lot of money by helping people stay healthy.
The "EPA conducted a formal cost-benefit study which found that the quantifiable benefits of its regulation would exceed the costs up to nine times over—by as much as $80 billion each year," she wrote.
"Those benefits include as many as 11,000 fewer premature deaths annually, along with a far greater number of avoided illnesses."
The standards were adopted in 2012 and were to have taken effect this year, requiring coal or oil-burning plants to drastically reduce their mercury emissions.
The pollutant is considered especially toxic to children and pregnant women.
The Supreme Court ruling is a blow to the Obama administration and comes on the heels of two historic rulings last week that supported progressive causes—legalizing gay marriage across America and upholding the Democratic president's signature health care overhaul.
Republicans, who spent recent days blasting the Supreme Court over the decisions, were relatively muted after the mercury ruling.
"#SCOTUS took an important step to help ensure the EPA takes into account the true cost of excessive regulations on the American people," Republican Senator Steve Daines of Montana wrote on Twitter, using the acronym for the Supreme Court of the United States.
Kevin McCarthy, the Republican House majority leader, tweeted: "The fact that the #EPA wished to ignore the costs of its rules demonstrates how little it's concerned about the effects it has on Americans."
The challengers of the regulation included states led by Michigan, a coalition of power plants and the National Mining Association.
Copyright Agence France-Presse, 2015