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.
In a widely reported case, the U.S. Environmental Protection Agency last week dropped legal charges against Range Resources Corp. over allegations that the drilling company had polluted water wells in Texas.
In late 2010, the federal agency charged that Range wells were leaking natural gas into two homes in the Fort Worth suburbs.
Range was ordered to fix the problem and provide safe drinking water.
the company disputed the charges. saying the EPA's analysis was inconclusive. It pointed to nearby water wells that were known to contain high concentrations of gas long before it began drilling.
A state commission had suggested that the methane gas most likely seeped into the aquifer from a shallow pocket of gas nearby, not the Barnett shale thousands of feet below ground.
The EPA last week lifted the emergency order and agreed to drop the case.