AKRON, Ohio (AP) - Millions of gallons of drilling waste have been injected underground in Ohio, leading some to worry about possible ties to earthquakes.
The drilling practice known as hydraulic fracturing uses chemically-laced water to free oil and gas from underground shale formations. Ohio has 181 wells to inject waste fluid underground.
The Akron Beacon Journal reports that nearly 50 percent of the drilling waste comes from Pennsylvania, which last year banned shipment of the liquid to state water treatment plants.
Experts suspect that the drilling fluid can trigger earthquakes along geological fault lines by allowing rocks to flow more easily past one another.
Injection well operators say there is no clear link between earthquakes and fluid being pumped underground.