WASHINGTON -- The Obama administration is issuing the first-ever standards to control air pollution from gas wells that are drilled using a method called hydraulic fracturing, or fracking.

But the administration, which has strongly backed natural gas drilling, made significant concessions to the oil and gas industry.
The regulation is expected to be officially announced later Wednesday.

Administration officials who briefed The Associated Press in advance of the announcement said drillers would be given an additional two years to comply with the rules. Wells drilled in low-pressure areas which release less air pollution would also be exempt. Hydraulic fracturing has spawned a natural gas-drilling boom, but has raised environmental concerns for its toll on water and air.

By DINA CAPPIELLO Associated Press