Chesapeake Energy Corp,the Oklahoma-based firm is the No. 1 driller in Ohio.
Rig Count Interactive Map by Baker Hughes, an energy services company.
Shale Sheet Fracking, a Youngstown Vindicator blog.
The Ohio Environmental Council, a statewide eco-group based in Columbus.
Earthjustice, a national eco-group.
People's Oil and Gas Collaborative-Ohio, a grass-roots group in Northeast Ohio.
Concerned Citizens of Medina County, a grass-roots group.
No Frack Ohio, a Columbus-based grass-roots group.
Fracking: Gas Drilling's Environmental Threat by ProPublica, an online journalism site.
Pipeline, blog from Pittsburgh Post-Gazette on Marcellus shale drilling.
Allegheny Front, environmental public radio for Western Pennsylvania.
From the Associated Press:
Police say they're investigating reports remains of small explosive devices were found at two natural gas drilling sites in northeastern Pennsylvania.
Shell Oil Co. spokeswoman Kelly OpDeWeegh said in an email Thursday the company contacted state police on April 12 after "charred debris" was found at an inactive drill site in Tioga County. Shell also informed authorities of a possibly similar finding on a different pad on March 21.
State police spokeswoman Maria Finn says there are no signs people or drilling operations were in any danger. She says the investigation into "possible components associated with small explosive devices" is ongoing.
Houston-based Shell says the FBI also is involved.