Congress first adopted clean air standards for power plants 20 years ago, but they were stalled by court fights, economic arguments and politics.

Now the EPA is giving power companies up to five years to implement controls that it says will prevent 130,000 cases of childhood asthma and 11,000 premature deaths each year.

Melissa McHenry is a spokeswoman for Columbus-based AEP. She says the utility doesn’t object  to the standards just the time line.

"We had hoped to extend compliance for the whole slate of EPA rules through 2020. There would still be emission reduction in the meantime as plants were shut down and as emission controls were installed on other facilities. It's just with every coal plant seeking to retire or comply by installing equipment, you are going to have a lot of pressure on supplies of both labor and materials. "

AEP operates five coal-fired power plants in Ohio, and estimates an upgrade could cost as much as 8 billion dollars.

Natural  Resources Defense Council attorney Emily Davis says the investment is worth it, and that coal power plant owners have known for years tougher that regulations were coming.

"For every one dollar spent by a power company, the American people will see up to nine dollars in health savings. That means you know avoided trips to the emergency room, less asthma attacks in children, avoided premature deaths from air pollution. And so those are benefits that have been long overdue as a result of the delay in the standards."

Northeast Ohio’s other major electric utility, FirstEnergy, says it could need as much as 3 billion dollars to upgrade its dirty plants.