Georgia has joined 16 other states in a legal challenge urging federal environmental regulators to reverse a decision that could force utilities to reduce more carbon emissions. But the state has yet to decide whether to fight the Obama administration’s broader restrictions on existing power plants.

The petition that Attorney General Sam Olens filed this week claims an Environmental Protection Agency rule requiring Georgia to revise its air pollution cleanup plans will increase costs for industrial plants while offering only a “negligible” impact on the environment.

The legal fight involves the “State Implementation Plans” that Georgia and other states must develop to comply with federal air standards and cut emissions that could be harmful. The EPA recently issued an order requiring Georgia and 34 other states to revise the plans as a result of a legal settlement with the Sierra Club, the environmental lobby group.

“It is important for Georgia power plants and industries to keep living up to their responsibilities on overall emissions,” Olens said, “but this new mandate is simply the result of EPA working with the Sierra Club in yet another example of ‘sue and settle’ decision-making.”

Federal regulators did not immediately respond to requests for comment about the legal challenge. The Sierra Club of Georgia accused the state of trying to perpetuate an “irresponsible and dangerous giveaway to polluters” that threatens residents who live near coal-fired power plants.

“Georgia’s attorney general has developed a bad habit of putting polluters over people, challenging mercury and other clean air programs at the request of utilities and over the objection of state agencies,” said Colleen Kiernan, the Georgia Chapter director for the Sierra Club. “However, EPA is required to close these loopholes because they are inconsistent with the Clean Air Act.”

The challenge comes as Georgia grapples with President Barack Obama's separate plan announced last week to reduce power-plant emissions in Georgia by 25 percent. Georgia did not join other Republican-led states in challenging the Clean Power Plan restrictions after regulators agreed to let the state up the amount of carbon emissions power plants can release.

The states’ challenge to the rewrite of the “State Implementation Plans” has been brewing for months, and Gov. Nathan Deal sent a letter on July 28 saying the rule change “could create a serious threat to electricity generation reliability, especially during extreme weather seasons.”

“Of even greater concern to us are cost increases on the public,” Deal wrote in the letter to EPA Administrator Gina McCarthy. “The increase in energy costs for job creators and employers is concerning enough, but we believe endorsing cost increases on low-income families and senior citizens, those who can least afford it, is irresponsible and careless.”