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.
Oil production int he United States has grown for the first time in 25 years.
North Dakota is the No. 2 oil-producing state thanks to the Bakken shale.
It trails only Texas in oil-production output, says Pro Publica.
The growth has come at a cost, however, in the form of millions of gallons of salty, chemical-infused wastewater, which oil companies have been spilling and dumping into the region with increasing regularity.
Nicholas Kusnetz reports that drillers are supposed to inject this brine thousands of feet underground into disposal wells, but some of it isn't making it that far -- wiping out aquatic life in streams and wetlands in the process.
Compounding such problems, state regulators have often been unable -- or unwilling -- to compel energy companies to clean up their mess, he says.
"Under North Dakota regulations, the agencies that oversee drilling and water safety can sanction companies that dump or spill waste, but they seldom do: They have issued fewer than 50 disciplinary actions for all types of drilling violations, including spills, over the past three years," Kusnetz writes.
You can read its story by clicking here.