The U.S. Supreme Court on Tuesday agreed to weigh a challenge by industry groups and some states to an Obama administration regulation intended to limit emissions of mercury and other hazardous pollutants mainly from coal-fired power plants.
In a blow to the administration, the justices said in a brief order they would review an April ruling by the U.S. Court of Appeals for the District of Columbia Circuit that upheld the rule.
The court will decide whether the U.S. Environmental Protection Agency should have considered the cost of compliance when deciding whether to regulate the pollutants.
The 2012 regulation - which also targets oil-fired plants, although these are less common - is being challenged by Michigan and 20 other states in addition to various industry groups, including the National Mining Association.
Michigan Attorney General Bill Schuette, a Republican, said in a statement the EPA's refusal to consider the estimated $9.6 billion-a-year costs "will result in rate increases for citizens across the country and threaten the reliability of the electricity grid."
The regulation could help spur utility companies to shut down some coal-fired plants due to the costs of compliance. The rule applies to 1,400 of the country's largest power plants and would come into force in 2015, or in some cases 2016.
Almost 65 percent of coal-fired plants already have pollution controls that comply with the regulation, according to the U.S. Energy Information Administration. The agency said 20 percent of plants face the decision of whether to upgrade or close down in order to be in compliance.
The EPA has said the regulation could annually prevent up to 11,000 premature deaths. The agency also said it could generate billions of dollars in benefits including a reduction in mercury poisoning, which can lead to developmental delays and abnormalities in children.
The rule is supported by environmental groups, including the Environmental Defense Fund. Vickie Patton, the group's general counsel, said the regulations "are thoroughly anchored in law and science."
The case marks the third time in little over a year that the court has agreed to review Obama air pollution regulations. In April, the court upheld a regulation that limits air pollution across state lines. In June, the court largely upheld the government's ability to regulate greenhouse gas emissions from major utilities.
A ruling is due by the end of June.
The three consolidated cases are Michigan v. EPA, 14-46, Utility Air Regulatory Group v. EPA, 14-47, National Mining Association v. EPA, 14-49.
