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.
Exploration of shale gas resources should resume after completion of an investigation into hydraulic fracturing, said the U.K.'s Environmental Agency.
"There are significant environmental risks associated with shale gas as there are with other industrial activities," said agency spokesman Tony Grayling. "We think those risks can be managed."
Bloomberg News reported that Grayling's comments come before a report from the Department of Energy and Climate Change that will rule on whether a moratorium on fracking will be lifted after Cuadrilla Resources Ltd. said it caused two small earthquakes last year.
That report is scheduled to be released for public review soon.