A large explosion and fire at a Chesapeake Appalachia gas well has injured three workers.
The explosion was reported at about 6:15 PM Wednesday in Independence Township, Pennsylvania, near Pittsburgh.
The fire started in several storage tanks that hold fracking fluid, a chemical compound that is pumped underground as part of extraction process of Marcellus Shale gas drilling, said Katy Gresh, a spokeswoman for the state Department of Environmental Protection.
The tanks that caught fire were holding flow-back fracking fluid, which had already been used in the drilling process, she said.
Two workers were flown to hospitals in Pittsburgh, a third was transported by ambulance.
The extent of their injuries was not known.
Gresh said the three wells at the western Pennsylvania site appeared to be unaffected. The wells are located in the Marcellus Shale formation.
An investigation will begin Thursday to determine the cause of the blast.
