In a 2-to-1 decision, the court ruled that the mercury rule "was substantively and procedurally valid," turning aside challenges brought both by Republican-led states that had argued the rule was onerous and environmental groups that had contended it did not go far enough.
The EPA welcomed the decision, calling it "a victory for public health and the environment." Liz Purchia, an agency spokeswoman, said, "These practical and cost-effective standards will save thousands of lives each year, prevent heart and asthma attacks, while slashing emissions of the neurotoxin mercury, which can impair children's ability to learn."
Environmentalists also hailed the ruling, which John Walke of the
The combustion of coal for power generation releases toxics such as mercury into the air. Through precipitation, mercury returns to the earth and changes into a "highly toxic" substance called methylmercury. Methylmercury enters the food chain and contaminates fish that people consume. The chemical is particularly dangerous for pregnant women, who can easily pass it to their fetuses.
The EPA estimates that the mercury and air toxics rule will prevent 11,000 premature deaths, 4,700 heart attacks and 130,000 asthma attacks annually.