* Pennsylvania natgas well blows out during fracking
* Local residents have been evacuated
* Fluid initially spilled into local waterway
* Incident comes exactly one year after BP oil spill
By Edward McAllister
NEW YORK, April 20 (Reuters) - A natural gas well spilled thousands of gallons of hydraulic fracking drilling fluid water in Pennsylvania on Wednesday after a blowout, state and local regulators said.
The well, operated by Chesapeake Energy (CHK.N), began spewing fluid at 11.45 p.m. on Tuesday during the controversial "fracking" drilling process which involves blasting shale rock with water, sand and chemicals to release trapped natural gas.
The spill comes at a sensitive time for energy drillers, exactly one year on from the massive BP Gulf of Mexico oil spill, and just as regulators are mulling whether to allow fracking in neighboring New York State.
"An equipment failure occurred during well-completion activities, allowing the release of completion fluids," Chesapeake said in a statement.
Local residents were evacuated from Leroy Township, Bradford County. No one was hurt, Chesapeake said.
The fluid initially spilled into a nearby waterway, though the flow has since been redirected.
Environmentalists and some neighbors of wells have complained that fracking can pollute water supplies.
The Pennsylvania Department of Environmental Protection has tested the water and found no adverse affects on aquatic life as yet, a DEP spokeswoman said.
The incident comes two months after Chesapeake shut natural gas wells in the Marcellus Shale in western Pennsylvania, after a fire in natural gas liquids storage tanks injured three people. [ID:nN24261147]
Chesapeake is considering building its own fracking business. It has 27 rigs operating in the large Marcellus shale play that stretches across parts of Pennsylvania and neighboring states.
Gas drilling in Pennsylvania, and in particular in the Marcellus Shale, has drawn the attention of major energy companies due to estimates that the region holds enough gas to meet total U.S. needs for a decade or more.
Additional reporting by Janet McGurty, Joshua Schneyer and Kristina Cooke; Editing by David Gregorio and Matthew Robinson