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.
U.S. Sen, Rob Portman, R-Ohio, announced today that he is pleased that the U.S. Environmental Protection Agency will review its controversial decision on hydraulic fracturing or fracking in Wyoming.
The federal agency decided to designate its draft report from Pavillion, Wyo., to be a "highly influential scientific assessment" that wil require a more thorough and transparent peer review.
Last month, Portman and U.S. Sen. Mary Landrieu, D-La., called for the EPA to make sure that the report released last December complies with legal standards of scientific integrity.
They called the EPA report "novel" and "precedent-setting."
The industry and others charged that the EPA report was inaccurate and flawed and could have potential impacts on state and federal regulations on drilling for natural gas.
The Wyoming report said that fracking might be to blame for causing groundwater pollution.
The EPA found that compounds likely associated with fracking chemicals had been detected in the groundwater beneath Pavillion, a small community in central Wyoming where residents say their well water reeks of chemicals.
Health officials in 2010 advised them not to drink their water after the EPA found low levels of hydrocarbons in their wells.
The EPA has emphasized that the findings are specific to the Pavillion area. The agency said the fracking that occurred in Pavillion differed from fracking methods used elsewhere in regions with different geological characteristics.
The fracking occurred below the level of the drinking water aquifer and close to water wells, the EPA said.
Elsewhere, drilling is more remote and fracking occurs much deeper than the level of groundwater that would normally be used.
Calgary, Alberta-based Encana Corp. that owns the Pavillion gas field disputes the EPA findings.
The compounds EPA said could be associated with fracking and could have had other origins not related to gas development, the company said.