U.S. House Republicans are again attacking new environmental regulationsthat limit the amount of mercury and other pollution power plants can emit. The new rules were finalized in December, and were the subject of a House subcommittee meeting today.The hearing, led by Kentucky Congressman Ed Whitfield, essentially can be summarized like this: Republicans question all of the data released by the Environmental Protection Agency, including the cost of the regulations and their effect on the economy.Kentucky Congressman Ed Whitfield chairs the subcommittee.“We’ve repeatedly asked, we’ve sent questions, we’ve sent letters, we’ve called, asking for the total cost,” he said. “And we still have no total cost. And we know this is the most costly regulation relating to utilities that EPA has ever submitted.”Gina McCarthy is the EPA’s Assistant Administrator for the Office of Air. She told Whitfield that the agency estimates the rule will cost $9.6 billion to implement in its first year, 2016. But McCarthy says it will generate anywhere from $37 to $90 billion a year in benefits (mostly health benefits), and cause a net increase in jobs. She told the committee that coal-fired power plants will still be able to operate under the rules.“The only thing we’re doing in this rule in particular is using available cost-effective controls to minimize harmful emissions of toxic chemicals that are impacting American families,” McCarthy said. “That does not mean that we are precluding any type of energy from being utilized or constructed.”But this was greeted with some skepticism, as members of the committee referenced other EPA rules limiting pollution from natural gas drilling.