(Reuters) - The Environmental Protection Agency is introducing its most ambitious clean air rules in decades, though it is making some concessions to election-minded Republicans who oppose them.
The EPA, facing backlash from heavy industry, has delayed several of the rules and made adjustments in others. Some industry groups say the rules will cost companies billions of dollars and increase power bills for consumers.
The EPA says money saved on healthcare costs will be greater than the amount polluters will need to invest in retooling plants to meet the new standards.
So far, the major delay in the rules has been President Barack Obama's backtracking in September on smog pollution, which came as a disappointment to EPA Administrator Lisa Jackson.
Below are important dates for the clean air rules:
* CROSS STATE AIR POLLUTION RULE
Finalized by the EPA in July, this rule aims to slash air pollution that blows downwind from coal-fired power plants in the eastern United States. Two days before it was to take effect, a U.S. federal appeals court delayed the implementation, pending further review, after power generators complained about the deadline. The first phase of regulation had been set to begin on January 1, 2012, and the second two years later.
* VEHICLE EFFICIENCY
The EPA and the Department of Transportation in December released a plan to double auto fuel efficiency to 54.5 mile per gallon by 2025. Regulators hope to finalize the proposal by summer following a 60-day comment period. The rules, which have rankled some Republicans in Congress, would start taking effect in 2017. Current standards require automakers to raise efficiency across their fleets from 27 mpg today to 35.4 mpg by 2016.
* MERCURY, TOXIC POLLUTANTS FROM POWER PLANTS
The EPA finalized rules aimed at slashing mercury and other toxic air pollution from power plants in December.The U.S. Midwest power grid operator has said this is the air rule that would close the most coal-fired power plants.
* GREENHOUSE GAS LIMITS ON POWER PLANTS
The EPA's Gina McCarthy said the agency would roll out by the end of January limits on emissions blamed for warming the planet from new power plants. McCarthy said the agency has no plans in the near term to publish rules for power plants and oil refineries that are already in operation, and which put out the bulk of the emissions. Release of the plan has been delayed twice, in June and in September.
* GREENHOUSE GAS LIMITS ON REFINERIES
The EPA said this week it would miss a mid-December target of rolling out the first ever greenhouse gas limits on oil refineries. An EPA source said the rule will not be rolled out until after the power plants rule is proposed.
* FRACKING EMISSIONS
In October, the EPA delayed by a month finalizing standards on emissions from hydraulic fracturing, or fracking, operations. The public comment period ended on November 30 and the rule will be finalized by April 3, 2012. They seek to cut emissions of volatile organic compounds that contribute to smog by nearly 25 percent across the oil and natural gas industry and by 95 percent from gas wells that use the technique of fracking.
The EPA plans to propose and finalize by spring 2012 a rule to cut pollution, including smog-forming chemicals and particles, that cause haze.
* COAL ASH
The EPA plans to determine this summer how to regulate coal ash, used in construction, but which can contain heavy metal and other toxic pollutants. In 2008, a massive retaining wall in Tennessee gave way and analysis of river water after the disaster showed elevated levels of pollutants that can cause birth defects.
EPA 2013 AND BEYOND:
* SMOG EMISSIONS
President Barack Obama in September backtracked on ambitious EPA limits on pollutants that cause smog, citing an effort to reduce regulatory burdens for business. The rule will now be reviewed in 2013. Until then, Jackson will have to enforce a George W. Bush-era smog rule she once called legally indefensible.
(Reporting By Timothy Gardner; Editing by David Gregorio)