Under an agreement between the White House and the EPA, power plant operators who have trouble meeting a three-year deadline for compliance will be given some flexibility, the newspaper reported on Friday. But details of the rules are not expected to be announced until next week. Citing EPA estimates, the Washington Post said the rules will cost utilities $10.6 billion by 2016 to install special control equipment known as "scrubbers." The new restrictions on coal plant emissions are part of the EPA's effort to roll out some of the most ambitious clean air rules in the United States in decades. It has faced a backlash from the industry and Republicans in the House of Representatives, leading to minor delays in some of its planned new regulations. In October, the EPA delayed approval of the mercury pollution rule, saying it needed more time to review the 960,000 comments it received on the draft of the measure. Friday was the date the EPA has said it expected to finalize the rules. In response to concerns about the costs, the EPA has said the money saved in healthcare costs will be greater than the amount polluters will need to invest in retooling their plants to meet the new standards. A group of 25 states has launched a court case over the rule, seeking a delay of at least a year for what they argue is an expensive measure that will shut down old coal-fired power plants. Analysts have said American Electric Power and Duke Energy could see shutdowns because of the rule, which would require many plants to install scrubbers and other anti-pollution technology. But the EPA, which has also been sued by environmental groups to finalize the rule, has maintained that the regulation is needed to prevent illnesses and deaths caused by air pollution.