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.
State Rep. Bob Hagan, D-Youngstown, announced on Friday that he will introduce a resulution in the Ohio Legislature calling for a federal investigation into ground water contamination from oil and gas injection wells.
The resolution, expected to be introduced in the next few weeks, is seeking a study by the Government Accountability Office on the environmental impacts of the injection wells.
Such a request must be approved by Congress before it can proceed.
The GAO, the investigative arm of Congress, last looked at the issue in 1989, Hagan said in a letter to U.S. Sen. Sherrod Brown.
Ohio has 176 wells and more are planned.They take briny wastewater from natural gas and oil wells. They also take fracking liquids. The waste is then injected under pressure inbto underground rock formations.
The Ohio Department of Natural Resources says injection wells are a safe disposal method.
Ohio's injection wells take large volumes of drilling waste from Pennsylvania.
A closed injection well in the Youngstown area is blamed for a series of 2011-2012 earthquakes.