The EPA says the investments would be far outweighed by the hundreds of billions of dollars in health care savings from cleaner air. The agency said the rule would prevent more than 30,000 premature deaths and hundreds of thousands of illnesses each year.
"The Supreme Court today laid to rest the well-worn issue of how to regulate air pollution that is transported hundreds of miles throughout the eastern U.S. and that makes it nearly impossible for states acting alone to protect the health and welfare of their citizens," said Bill Becker, the executive director of the National Association of Clean Air Agencies, which represents air pollution control agencies in 45 states and territories and 116 major metropolitan areas nationwide.
Texas led 14 states and industry groups in challenging the rule. Most downwind states support it.
States had argued, and the lower court had agreed, that they deserved a chance to figure out how much they were contributing to pollution in other states and how to reduce it before the EPA prescribed fixes. The lower court also faulted the EPA for requiring states to reduce pollution through a complex formula based on cost that did not exactly match how much downwind pollution a state was responsible for.
Agreeing with the EPA, Ginsburg wrote that the realities of interstate air pollution "are not so simple." She wrote, "Most upwind states contribute to pollution to multiple downwind states in varying amounts."
The lower court will still have to decide if the EPA acted properly when it rejected state plans that had been approved under an earlier version of the rule.
Opponents of the decision Tuesday said it violated the intent of the Clean Air Act, which envisions states and the EPA working cooperatively to reduce air pollution.
"The Supreme Court majority has refused to allow the states to have any voice in the practicalities of determining the impact of their emissions on neighboring states," said Richard Faulk, senior director at George Mason Law School's Energy and Environment Initiative.
As for legal grounds, Scalia said the majority had "zero textual basis" in the Clean Air Act for justifying the EPA's approach, and he mocked its analysis as "Look Ma, no hands!"
Ginsburg said Scalia's approach would result in "costly overregulation" and called it "both inefficient and inequitable."
Associated Press writer Mark Sherman contributed to this report.
Follow Dina Cappiello at http://www.twitter.com/dinacappiello