A federal court upheld an Environmental Protection Agency rule that limits mercury and other toxic air emissions from power plants Tuesday, delivering a victory for the Obama administration and a blow to industry groups fighting the regulation.

The U.S. Court of Appeals for the D.C. Circuit denied challenges to the Mercury and Air Toxics Standards, or MATS, which go into effect in May 2015. The rule is a key part of President Obama's environmental agenda, as it would force some of the nation's 600 dirtiest coal- and oil-fired power plants to shut down or install new technology to curb emissions.

The court rejected the arguments by petitioners, which included about two dozen states, that the EPA committed procedural errors in crafting and allowing comment on the rule.

"[W]e hold that EPA’s finding in the final rule was substantively and procedurally valid," the court wrote, explaining that changes the agency made to an earlier finding rendered the petitioners' complaints "moot."

The EPA says the MATS rule would significantly curb mercury emissions from power plants that, as the largest source of such pollution, account for 50 percent of the nation's total mercury emissions. It also would slash emissions of other heavy metals, such as arsenic and nickel, that have been linked to cancer and heart and respiratory ailments.

"Toxic air pollution from power plants can make people sick and cut lives short," said the American Lung Association, which was an intervener in the case. "Many of these pollutants, such as dioxins, arsenic and lead, can cause cancer and cardiovascular disease, harm the kidneys, lungs and nervous system, and even kill."

The EPA was backed by more than a dozen states, mainly on the West Coast and in the Northeast.

The EPA has estimated health benefits ranging between $37 billion to $90 billion in 2016, compared with a $9.6 billion cost to implement the rule.

"EPA is very pleased that the court upheld the Mercury and Air Toxics Standards, a decision that is a victory for public health and the environment. 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," said Liz Purchia, an agency spokeswoman.

But the electric utility industry says the rule could shutter enough coal-fired power plants to create electricity reliability concerns in some portions of the country. The industry, with its congressional allies, have pointed to this winter's cold snap that forced some utilities to run nearly all of their facilities scheduled to retire under the rule to meet unanticipated power demand spikes.

In letters last month to four of the regional regulatory organizations that oversee the electric grid, senior Republicans on the House Energy and Commerce Committee raised concerns that the MATS rule would handicap the ability to meet unexpected power surges.

"We are specifically concerned that the loss of these critical generation facilities in such a short timeframe will make it increasingly difficult to meet electricity demands in the future, thereby putting reliability at risk and driving up electricity prices for consumers," the lawmakers wrote.