The order, which comes in response to a court ruling, requires utilities to install devices that slash emissions of sulfur dioxide and nitrogen oxides — byproducts of burning coal that react with the atmosphere to form the particles that cause soot and smog.

“No community should have to bear the burden of another community’s polluters, or be powerless to prevent air pollution that leads to asthma, heart attacks and other harmful illnesses,” EPA chief Lisa Jackson said in announcing the rule.

While Jackson argues the cleaner air will improve public health, pushback already has come from some states and companies operating older coal-fired power plants.

They say the rule could prove too costly and that the timeline for compliance is too short.

Anticipating the EPA order, Oklahoma sued the agency in May, citing costs of up to $2.5 billion to install “scrubbers” that would reduce pollution from state coal plants.

That could drive up utility rates by as much as 20 percent, argued Oklahoma Attorney General Scott Pruitt.