EPA officials were in Philadelphia Friday to get public feedback for the next phase of the Obama administration's Climate Action Plan: limiting carbon emissions from currently operating power plants.

The EPA already has put rules on the table seeking to curb emissions from all new coal- and natural gas-fired power plants. That proposal is being challenged by several states that argue the federal government doesn't have the authority to issue such regulations. The EPA says it is directed to create guidelines for states to work out their own programs to address carbon pollution.

The Obama administration is targeting power plants because they are some of the biggest emitters of carbon dioxide, a powerful greenhouse gas.

"Fifty, 100 years ago, we didn't understand the down sides of burning fossil fuel, but we do now so we must move ahead," said Joy Bergey, federal policy director with the environmental group PennFuture.

But it can be a bitter pill to swallow in major energy-producing states such as Pennsylvania. The industry that's feeling the biggest pressure from federal regulators is coal.

"Many of us in our industry always feel like we're a target," said Tom Crooks, vice president of R.G. Johnson, a company in Washington County that sinks mine shafts.

"We want time to innovate because we need time to innovate," said Crooks, who argues the coal industry  already has been working on cleaning up its act for decades. "This is not something that can be done in the next couple years."

Environmental groups PennFuture and others in attendance at Friday's hearing say the Obama administration cannot afford to wait to address climate change.

But the final carbon regulations may be a few years off. The coal industry is supporting a Supreme Court challenge that is taking up the question of whether the EPA has the right to regulate emissions from smokestacks like it did with tailpipes on cars and trucks.