UPDATE 1-U.S. EPA seen delaying rules on greenhouse gases

* Delay of about a month seen

* EPA says has nothing to announce
(Adds details on regulations, companies potentially affected)

By Timothy Gardner

WASHINGTON, June 3 (Reuters) - The U.S. Environmental
Protection Agency, under the gun from Republicans and
struggling with an ambitious agenda, will likely delay by a
month proposing rules to cut greenhouse gas emissions from the
country's major utilities, sources said.

"We would not be surprised if it does not come out at the
end of July, if it slips by a month or so," said a source at an
environmental think tank, who works with states and federal
agencies and wished to remain anonymous.

The EPA said late last year it would propose rules on
constraining greenhouse gas emissions from power plants --
known as performance standards -- in July. It plans to propose
similar rules on oil refineries in December.

The rules will likely give polluters flexibility to cut
emissions by participating in existing or planned regional
cap-and-trade markets, for example, or by switching from coal
to cleaner-burning natural gas.

Large coal burners such as American Electric Power (AEP.N),
Southern Co (SO.N) and Duke Energy (DUK.N) would be most
affected by the rules, and forced to cut emissions blamed for
warming the planet or face penalties.

The timing of the EPA rules is important because President
Barack Obama has pledged to reduce U.S. emissions by about 17
percent by 2020 compared to 2005 levels.

The position has been criticized as inadequate at the
stalled world climate talks and U.S. emissions could rise
quickly if the economic recovery speeds up.

Because Congress failed last year to pass a climate bill,
the Obama administration has been relying on the EPA to spur
reductions in carbon emissions. The EPA began rolling out its
rules on the biggest polluters at the start of the year.

As a result, the EPA has taken on its heaviest load in
years and is struggling with a number of delays.

A rule on ozone pollution, which is hazardous to health,
has already been delayed several times. In May the EPA delayed
indefinitely the finalization of rules on pollutants, such as
mercury and soot, from industrial boilers that were supposed to
be implemented in coming years.

In the fall, the EPA plans to issue rules on greater
efficiency for vehicles.

NOTHING TO ANNOUNCE

Ahead of next year's presidential and congressional
elections, Republicans in the House of Representatives have
been trying to stop the agency from moving ahead on the rules,
saying the regulations will boost energy costs and hurt jobs by
driving businesses overseas.

Some Democrats facing tight races next year in the Senate
have also pushed to delay the EPA's rules or stop it entirely.

The EPA would not say whether it was considering a delay.
"We don't have anything to announce on this," an EPA spokesman
said in an email.

Environmentalists were watching the EPA closely to see if
politics entered into the decision. "We would be concerned but
not devastated" about a delay of a month or so, because the
EPA's workload is so heavy right now, said Frank O'Donnell, the
president of Clean Air Watch.

But he said heavy opposition from Republicans and industry
had already led the EPA to delay rules on ozone and other air
pollution issues, so a delay of longer than a few months on
greenhouse gases would be worrisome.

Many in the energy industry say now is not the right time
for greenhouse gas rules. Power industry lobbyist Scott Segal,
of Bracewell & Giuliani, said that complying with the
greenhouse gas rules, combined with other rules on pollutants,
could affect the reliability of the electric grid.

It was unclear whether a delay in the proposal of the
greenhouse gases rules would affect when they would be
finalized. The EPA said in December that greenhouse gas
standards on power plants would be finalized in May 2012 and on
oil refineries in November 2012.
(Editing by Marguerita Choy and Dale Hudson)