The final rules also included some of that flexibility by holding off on implementation until 2016 at the earliest, giving industry more time to comply.
John Walke, director of green group Natural Resources Defense Council's clean air program, said the rules were an improvement but added that they are "mixed bag."
"The agency, however, eased standards in their final rules for cement manufacturers, which is troubling and deserves further explanation," Walke said in a Friday statement.
Industry groups were not pleased either.
Jay Timmons, chief executive with the National Association of Manufacturers, said the rules "remain far from being realistic."
"Manufacturers are understandably growing more pessimistic about the direction of the economy. The end-of-year regulatory assault on businesses, combined with the uncertainty of the fiscal cliff, makes for one of the worst business environments in living memory," Timmons said in a Friday statement.
The Capitol Hill reception was a bit warmer.
Sen. Ron WydenRon WydenWhy Trump should abolish the White House faith office Schumer puts GOP on notice over ObamaCare repeal Lawmakers condemn Trump for attack on John Lewis MORE (D-Ore.), who will head the Senate Committee on Energy and Natural Resources next Congress, said the rules strike "a good balance."
Rep. Ed WhitfieldEd WhitfieldWhy Republicans took aim at an ethics watchdog What Azerbaijan wants from Israel? Overnight Energy: Green group sues Exxon over climate science MORE (R-Ky.), who chairs the House Energy and Commerce subcommittee on Energy and Power, said that while he is still concerned about costs, the final rules "include changes that will help facilities achieve compliance."
”We welcome EPA’s revisions to make these rules more workable and achievable. EPA itself acknowledged that its original rules were flawed and rightfully commenced a reconsideration process," Whitfield added in a Friday statement.
Rep. Edward MarkeyEd MarkeyWHIP LIST: How many Dems will back Sessions? Confirm Inga Bernstein for the District of Massachusetts FCC takes aim at AT&T, Verizon over 'zero-rating' services MORE (D-Mass.), the top Democrat on the House Natural Resources Committee, praised the rules. He painted them as a victory for Democrats, noting Republicans had tried to derail the rules.
“Cutting mercury pollution from these industrial facilities will protect our children and cutting carbon pollution from these boilers will help heal the climate. From cars and trucks to power plants and now industrial boilers, the Obama administration is showing it is committed to cutting pollution," Markey said in a Friday statement.
— This story was last updated at 1:05 p.m.