SCOTUS Overturns Mercury Rule

The Supreme Court, in a 5–4 decision, ruled that the Clean Air Act required the U.S. Environmental Protection Agency (EPA) to consider the costs of its Mercury and Air Toxics Standard (MATS) rule when determining whether it was “appropriate and necessary” to regulate mercury emissions from the power sector.

The MATS rule requires coal-burning power plants to reduce emissions of toxic pollutants by installing control technologies. The EPA estimated MATS would cost industry about $9.6 billion a year but cut coal and oil emissions by 90 percent and generate $37 billion in savings through “co-benefits.” Because these benefits are calculated on the basis of increased life expectancies and reduced health effects, the values have been subject to much of the debate.

“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,” wrote Justice Antonin Scalia for the majority. “Statutory context supports this reading.”

The Supreme Court did not dictate how the agency should address its ruling. It sent the case back to the U.S. Court of Appeals for District of Columbia Circuit for reconsideration of the rulemaking.

“EPA is disappointed that the court did not uphold the rule, but this rule was issued more than three years ago, investments have been made and most plants are already well on their way to compliance,” said EPA spokeswoman Melissa Harrison, noting the agency is reviewing the ruling.

The Nicholas Institute for Environmental Policy Solutions’ Climate and Energy Program Director Jonas Monast notes that the immediate impact of the Supreme Court’s decision will likely be limited because electric utilities have already taken steps to comply with the regulation.

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